Yes, I used Android tap to pay extensively on my trip in August, including cafes, restaurants and vendors.
I've had vendors at the Grand Bazaar give me one (bargained) price for cash and another (higher) price for credit card.
In some touristy places, I was able to add a tip to a restaurant tab, but not always. One cafe couldn't figure it out. Either everyone leaves a small cash tip, or none.
I was glad to have cash for a few things: tips for hotel room staff, regular purchases of water bottles, which cost $0.30 - $0.90 (in August, depending on where I bought them); small purchases from market vendors.
I was even able to use my Android tap to pay for ferries, though I had some trouble with my phone on the buses. I'm not sure if that was because I was in a hurry and didn't hold the phone long enough. I used my credit card tap to pay on the buses with no problem. On any of the transit systems, you must hold your phone flat on the scanner and wait for it to beep or light up (or otherwise indicate success) which took longer with my phone than with my credit card.
Edit: I think the buses were the only time that I took out my physical card. For any other credit card purchase, I used Android tap to pay.