It's not a terrible 'value' when it's full. But this is a company and they are trying to part you from your dollars.
And as far as sales - the vault makes you think you've invested all this time into the game - so, you may as well put in just a few $ to get that investment back out. It's not the first game to do this.
Just accept game companies do want to make money. If you are unwilling to part with your $$, ignore it and appreciate they're trying to make a profit and keep the game running.
If vault really is stupid and doesn't work - it'll run 3-4 times and then you'll never see it again. Self correcting.