[k310]

I don't like taking the phone out of its slipcase any more than necessary.

(It's a small phone and perfectly fits a very old camera case that holds some adapters in a pocket)

Any more than to pay. The advantage to paying with the phone is that through regular but not constant use, I am very unlikely to misplace it.

As noted, I sometimes do both. I think that my old shopping app fell by the wayside (as apps sometimes do) and I never replaced it.