This would be useful in general, even if other solutions were present too. Also being a keystroke (e.g. space bar in particular) would be preferable to a mouse-click I think.
Getting out of the pause: perhaps just an unpause button that both must press
[runner hits spacebar - PAUSE]
runner: need to play clot
corp: ak kk
runner: k, go
[game unpauses as corp and runner press their respective buttons]
runner installs clot
I think it's a neat idea that has potential, but I'm not sure it has enough reward to warrant inclusion - the game can just move too fast and setting up the right trigger could involve a lot of configuration as triggering at the wrong time would give away your strategy.
What about just a one second gap between each click? It's possible that this inconvenience could be reduced by the game state could identify whether there's any rez or paid ability opportunities on the board for each side (e.g. no at the beginning of the game, but yes for the corp as soon as there's face down cards in servers) and not enforce the gap if there's no possibility of interruptions. Not super sold on this idea at all, but it's better than the obvious one of confirming you have no actions each turn and is a relatively generic mechanic that doesn't require specific implementation.