I had the opportunity to try this out yesterday. It works surprisingly well. Crew delivered everything to my seat (gummy bears on first flight, tacos on second flight) before the beverage service started. There was no friction or fumbling around with the crew iPhone to confirm whether a card was on file (to then not charge me as 1K).

This is a net improvement, especially for anyone who prefers exit row seating. In my experience, bistro on board items would often sell out by row 10-12 because the front few rows of E+ are all 1Ks claiming their free hot item.