As a DM, we sometimes have to balance the “Rule of Cool” with game balance in general. If you have a player that wants to do something nuts once, that’s one thing. I can speak from experience saying that, when making those at-the-table decisions, the question of “what if this becomes a regular thing? That would break things and unbalance the game!!” is definitely there.
Why not both?
There’s absolutely nothing stopping us from saying, “Normally, I’d say no, but in this particular case, sure, go ahead.” If, later, the player tries again, you can easily say, “Yeah … probably not this time.”
I’ve done this myself, and it works pretty well for allowing the one-time cool moment without giving the player an expectation of this-is-how-things-are-now.
Now get out there and tell a story!