I often forget when outside the US and leave tips...in places where tips are not common.
I'm told that's one way they know where a person is from, because US visitors always leave tips, whether customary or not. It's a relief in other countries to find servers who are just doing their job and getting paid adequately for it - without having to perform like a dancing monkey for a tip.
What I see happening now in the US is different. To me, the tipping screen for digital payment, seems a way for companies to get customers to subsidize their labor costs and is in no way related to the traditional concept of tipping for service, according to the service.
When someone hands me something over a counter and presents the tipping screen, I ask them where the cash jar is for tips.
As far as table service, of course, as always, add a tip or leave cash separately....it needs to direct to the server.