It can work as a tunic. Not that I have worn mine that way, but I did try it on that way and it looked really good. Might work with crops underneath, too -- actually.
I have only worn my Vince dress twice so far...but I know I will wear it again in the early autumn to a couple of events. And the following autumn as well. And maybe the one after that, too.
I don't consider that a fail. Yes, it cost a fair bit, but my "fancier" dresses are all like that. I tend to get them on sale (as I did this one, at NAS) and keep them for about five years, and even so, their cost per wear remains high. But so what? I have something in my closet to wear when I need it and I feel great in it.
Believe me -- I have been that woman who has nothing to wear for the event she's invited to or has to attend, and it is not good, and you waste more money (and time) in the fruitless search for something at the last minute.
For me, it's more -- do I have too many of these fancy dresses? If so, that's a problem. But if I have one or two to choose from for any type of temperature condition, then that seems reasonable, given my casual life that still includes some more dressy events.
Sorry for the threadjack, Marianna!