If OP is part of a bigger breach, those data dumps will almost certainly get analyzed automatically and multiple wallets swept at once. Passwords to interesting stuff likely aggregated and then tried. It’s not some script kiddy that browses through the vault 1by1
(a) Trivially accessible Bitcoin is stolen or (b) passwords are used to ferret items/info of value out of additional individual sites
For OP's plan to fail, someone has to leave $15k laying on the table, in plain sight and for the taking, while they plan their subsequent moves. Which is why the amount matters.
Your average attacker might be equally motivated to go for $20k, or $10k, or $5k. $1k, maybe not. $100, probably not. $1, almost certainly not.
There's an interesting game to play in minimizing the cost at no hit to efficiency.
It's a question about not touching an easy $15k, in exchange for a chance at a bigger score.
I'd assume most attackers wouldn't be able to resist securing the low hanging fruit first.
And even if there's a parallel move, it's even less likely they would leverage everything but the $15k, so OP would still receive a realtime indicator of compromise.
From a game theory perspective, it's a pretty compelling trap for OP to get what they want.