Short answer is: In Classical Chess you are forbidden to put (or leave) your king in check (if you can't avoid it, you lose).
That's exactly the reason you can't put your king in check merrily (even in the event you think you can win by leaving your king in check "just for a moment") because you'd need an immediate second move to take it from danger (a ...
It could be risky since you don't know what you have missed, but on the other hand, if you are low on the clock say under 10 minutes you might just have to go for the checkmate if the time control is also distant. Although playing while being a Queen up shouldn't be difficult even if you are a queen up.
you play a combination that is technically stronger since it forces mate, but it takes 8 moves, some of which are hard to see
If they're hard to see, chances are that you've missed something as well. Therefore, take the queen. You might miss the opportunity to finish the game in a beautiful way, but you can always save that for the post-mortem analysis.
I think that is limited to just a few positions.
A lone king vs. king.
king and bishop vs. king.
A king and bishop vs. king and same colored bishop as the other side.
A king and multiple bishops of the same color vs. king.
A king and knight vs. king.
Any barrier position, where neither side can cross over to the other side.
Even king and knight vs. king ...