>Getting another popup to confirm the action would be annoying.
Every bank system or stock trading app I ever used worked that way though. Giving an order summary seems like an obvious solution, giving the user a way to check and to unambiguously opt out if there is a mistake.
Buttons aren't there to be cancelled mid press, the interaction makes very little sense.
On my banking app I get a review screen as you described and I wouldn't be happy if the submit action would be triggered on press, because I'm already used to confirmation actions to be triggered on release.
And just look at this comment thread, quite a few are used to this as well, so changing it would upset those users. It's also not a repeated action, so you won't really notice the difference that much compared to pressing buttons on a virtual keyboard.
For non committal action button as per the examples above - yes use on press.
Every bank system or stock trading app I ever used worked that way though. Giving an order summary seems like an obvious solution, giving the user a way to check and to unambiguously opt out if there is a mistake.
Buttons aren't there to be cancelled mid press, the interaction makes very little sense.