You could also have much better safety systems - I.e. total oxygen evacuation for grease fires. No need to worry about people getting hurt. In fact, you might be able to make food in a 100% neutral environment (N2?) and have no fire risk at all. Then, you can use closed-loop air filtration and not exhaust grease and combustion byproducts into the atmosphere.

OTOH, the nice dining experiences will be done by people who can improvise and improve day-to-day based on their own tastes. eventually, the stuff people do will be the "good" stuff, and the stuff robots do will be the "bad" stuff. Hopefully. A more negative viewpoint says that robots will do the "high value" stuff and the people will only do the "low value" bad stuff.

No need for total oxygen evacuation. You actually just have to drop oxygen content in the air down from 21% to 15% to make most substances (including oil and grease) inflammable, and this air is perfectly safe to breathe for humans.

In fact, if you consider the partial oxygen pressure (which is what matters for your lungs), this air is no worse than the air you find inside an airplane, or at a 2500m (8200 ft) mountain peak; Wikipedia says 140 million people live permanently at above 2500 m.

Now, this already exists and is called a hypoxic air fire prevention system, and is used e.g. in some data centers and in archives of valuable documents. It's not used in fast food restaurants though, because they have better ways of preventing and extinguishing fires at lower cost.

By the way, "inflammable" is a synonym of "flammable". Try non-flammable, or "no longer flammable at that level".

There are some issues with human consumption of anerobic bacteria and their byproducts. If you thought the food poisoning from aerobic bacteria was rough, try some of the more exciting anaerobes.