My wife uses it all the time. Puts money into an account and she transfers to bank account after she gets a decent amount built up ($100). She uses it for groceries mostly, but rarely for fuel.
I just asked her, she said she’s going to grocery store in a bit, and currently will get 4% of spend back, several other sandwich shops/fast food places she just looked at currently giving back 15-18%.
She just checked the app and said she’s received $268 back in the last 11 months. Not too bad for no cost app.