Really depends on the restaurant.

The smaller or local places where we are have all mostly switched to the handheld mobile devices.

The fast food places are all still front register POS style.

The larger chains or fancier restaurants are mostly still take your card away and run it then return for a signature.

I imagine the holdouts either don’t want to make the technological and cost investment to update (big chains) or they feel the mobile device is too “low class” (fancier restaurants).