I'm not sure this should be applicable to critical actions, like completing a bank transfer, buying shares, etc.
For non critical actions where there is an easy undo - yes go ahead, e.g. in his example for an on-screen keyboard it makes sense. If you make a mistake you can easily undo it. But not when it comes to completing a major transaction.
Why? If it is critical give the user a confirmation screen where he can review his order.
That is, much, mich better than relying on the user realizing his mistakes 50% into the click and then figuring out how to get the computer to not continue.
I'm speaking from personal experience, I don't have quantitative data. If I'm on a review / confirmation screen I would prefer the action to be triggered on release - that's how other forms work and I gotten used to it working that way. Getting another popup to confirm the action would be annoying.
For other actions like adding stuff to a basket, increasing number of items etc, yes use on press.
>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.
For non critical actions where there is an easy undo - yes go ahead, e.g. in his example for an on-screen keyboard it makes sense. If you make a mistake you can easily undo it. But not when it comes to completing a major transaction.