Das ist keine vernünftige Antwort, was soll der Blödsinn ?

Um auf die Frage zurück zu kommen :
Was soll der Vorteil an dieser doppelten taggerei sein ?

"zahlenmäßig weiter verbreitet" ist eine quantitative Aussage, keine qualitative. ist die Logik entsprechend "Millionen Fliegen können nicht irren" ?

2 tags anstatt einem : amenity=canteen

Was soll der Vorteil an dieser doppelten taggerei sein ?

The source is mainly the homepage, motorcycle tours is from here :
http://www.illyriaraid.com/20/ass-teams-20.html
Merged the POIs, thanks for the hint.

I'd appreciate if you'd follow your approach as it makes no sense if only us two discuss it here quite "hidden". Regarding your semantic logic, the different accommodation types could then also be put into one "main" tag ? But car / car_repair / car_parts as separate shops really don't make sense, this should be expressed in a namespace, as otherwise you'd need multiple nodes if a shop offers several. Regarding the latter, I tried twice via the mailing list, but even the current mess regarding "services" didn't lead to an outcome.

Forgot to mention that most use "restaurant", but then the access tag should necessarily be used and self_service added
osm.wiki/Key:access
osm.wiki/Key:self_service

So you consider a canteen a subcategory of fast food ? And a key consisting of two keys desirable ?
Why not call it what it is ?
"a place where food and drink are served in a factory, a school, etc."
https://www.oxfordlearnersdictionaries.com/definition/english/canteen
"Service chargé de la préparation des repas pour les ouvriers ou les employés d'un même établissement, les élèves d'une école, etc."
https://www.larousse.fr/dictionnaires/francais/cantine/12806

Das mit der app kann ich nachvollziehen, ist aber ein generelles Problem. Wenn es beispielsweise eine "Philosophie" dazu gäbe, "canteen" als Unterkategorie von "restaurant" zu sehen (ohne Bedienung, ggf. access beschränkt), wäre das auch eine Lösung. Scheint aber mit den derzeitigen "demokratischen Mitteln" nicht (innerhalb einer Dekade) herstellbar.

Das hiesse eine Kantine wäre eine Unterkategorie von fast food ? Die meisten scheinen das anders zu sehen und nehmen "restaurant" (oder gar nichts) für "Mensa". Der Rest nimmt überwiegend "canteen", jedenfalls hierzulande.

service:vehicle:car_repair yes
service:vehicle:inspection yes
service:vehicle:oil_change yes
service:vehicle:repairs

I see what you mean, but IMHO everything is included in "repair" ?
Or are there wirkshops which offer repair, but no oil change and inspection ?

Please also see the "discussion" here :
https://lists.openstreetmap.org/pipermail/tagging/2019-January/041804.html
(unfortunately there weren't any opinions regarding the topic yet)

Gefällt mir, ausser dass jetzt an 4 Stellen diskutiert wird. (forum, taggingliste, wiki-Eintrag-Diskussionsseite und namespace-Diskussionsseite). Es wird höchste Zeit, dass mal ein Standard her kommt (ich bin für das KISS-Prinzip). Versuche das schon seit geraumer Zeit anzubringen, stosse aber nur auf taube Ohren. Bzw. wird nicht reagiert : https://lists.openstreetmap.org/pipermail/tagging/2018-May/036119.html

car:repair=transmission_rebuild would be fine ?
car:bodywork=yes also ?
This reduces the number of "phantasy" tags and makes it more traceable as well for apps and for humans (taginfo/overpass). Additionally, this is the 4th "namespace system" for vehicles. Imagine (or search for) "mixed shops" which offer services for several vehicles.

And what to do if I already mentioned the problem on the tagging list and there were no measures taken to avoid a mess (by "unauthorised" and undocumented changing of the car tagging scheme in the ID editor) ?
See
https://lists.openstreetmap.org/pipermail/tagging/2019-January/041799.html
And this hint :
osm.wiki/Tag:shop%3Dcar#Tags_used_in_combination

Naja, genau genommen wurde das tagging (nicht wiki-konform) von techies willkürlich angepasst, daher die hohe Anzahl sinnloser tags (nicht auswertbar oder standardisiert)
Ein Hinweis dazu hier :
osm.wiki/Tag:shop%3Dcar#Tags_used_in_combination

IMHO there's no car:repair which does NOT offer this ("yes" means "the full stack") ? In case a shop ONLY offers it you could use car:repair=service;oil_change. But this is currently being discussed :
https://lists.openstreetmap.org/pipermail/tagging/2019-January/041799.html

"considering the validity of those infos"
yes, I was, and tried to save as much as I could, also considering this principle :
https://en.wikipedia.org/wiki/Standardization#Effect_on_consumers
At least there were a lot of "useless" (not machine-readable as not standardised) entries, did you consider them as valuable ?

Yeah, that's a general problem with the brand tag. In case of several brands you're forced to separate them by semicolon.
You may choose your favorite using taginfo :
https://taginfo.openstreetmap.org/search?q=brand%3DVolkswagen
https://taginfo.openstreetmap.org/search?q=brand%3Dvw
and you may define a standard for it in the wiki :
osm.wiki/Tag:brand%3DHarley-Davidson
In wikipedia, they also got the two definitions :
https://en.wikipedia.org/wiki/Volkswagen

Please check
https://lists.openstreetmap.org/pipermail/tagging/2018-May/036119.html
and
https://lists.openstreetmap.org/pipermail/tagging/2019-January/041773.html
an take part in the discussion yourself