It's called having An Ace Up Your Sleeve. Knowing it's there releases endorphins. Using it probably inhibits your serotonin re-uptake.
(from the other question) What can you do to encourage the player to make use of their one-shot items and not hoard them?
I don't know, because it took me over twenty years to start using them. It's somewhere between IDGAF anymore and playing to win.
So really, you don't want, to want me, to use them. By that point I just want to see the ending, or it isn't my first playthrough. Or I see it as the ones and zeros of the Matrix. If that happens, unless the gameplay itself is entertaining, I'm done with it.
