Well, it lets you keep the points, so my "intended use" would be getting rid of Victory cards while mantaining the points. Of course you can use it to get rid of starting stuff, in a much weaker way than chapel (but pretty much everything is slower than chapel at getting rid of copper/estates).
For example, you can tune your lieutenants to Duchies and start duchying earlier (note that each duchy will hurt your draw at least once anyway), or to Provinces and never have your deck really slow down or to Estates, getting rid of them and then also storing any spare ones you might throw at it later.
It might be too slow, so I'm considering letting it set aside an unlimited number of cards per turn, or even letting it do it at any time during one's action phase, but that's a tad too long to write I think.
Of course this card would shine in games where you'd expect to see each victory card you buy at least twice after you've bought it, so slowish games or alt-vp or maybe even early-greening strategies built around lieutenant.