The limit varies by clearing house. In the UK it's possible that the limit is super-high if you unlock your phone with two-factor first. I've spent over a hundred pounds in one contactless transaction with my phone.
I use g-pay all the time, linked to both my main bank account and to my day-to-day card. Sometimes it doesn't work, but that's rare these days. Certainly I encounter more "cash only" places in Germany than I encountered places which took contactless but not g-pay.
"when prepared according to instructions" should dammed well include the food items in the instructions. I'm 300kcal off on my estimates of tonight's dinner. Argh
Sadly the one I love the most is one I wrote for some non-public software. What I love the most about it is that I wrote a Rust proc-macro to generate them so they're typesafe :D