I’m not sure if it needs a huge investment. Does a system like this get better as you invest? 100%. But if it’s contextual it might have such low friction that you barely notice using it. Like you add a note “Curry 8/10”, and that note gets automatically added to the restaurant (since that’s where you were when you made the note). Next time you go (or plan to go), it would pop up your previous experiences without needing extra taps.

Restaurants are more complicated because of the social view of checking your phone while out with people, but I think a similar place where it shines is the grocery store. The number of times I bought the same flavour of listerine that I can’t stand is upsetting.