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The opposite of takeaway= etc was discussed somewhere before, possibly for features that normally don’t have it, or to distinguish counter service (some =fast_food actually have staff serving the meal to you for some special items) as both are dine-in. self_service=yes alone doesn’t show whether there is another option for waiter service.
There are 9 table_service | Keys | OpenStreetMap Taginfo , and maybe add restaurant=yes . The latter causes an overlap between “there is a restaurant” vs “this is a restaurant” (sorta) , and it’s unclear whether it is inside or outside.
Food tagging could be considered orthogonal to theatre*= . There is potential usefulness in showing them when you are looking to eat somewhere, while you aren’t exactly looking for them specifically. The performance might be considered as a “complimentary” entertainment, if you can easily afford this extra perk.
As you have shown, different dinner theaters can provide different shows, so it requires the usual theatre:*= tagging for that aspect. It’s applicable to =cinema as well. Therefore, a generic feature-independent attribute is desirable.