Unless, like the original, it's half the price of comparable systems or less.
Which, unfortunately, it's not. A VIC-Slim that's actually functional (i.e. comes with the OS, hard drive, RAM, etc.) will run you $545 for the "standard" model, or $595 for the "supreme" model. That's pretty much on par with a standard desktop PC these days.
(And those Commodore 64X machines are even worse; a functional model will run you over $1000!)
I can see the VIC-Slim being useful for environments where space is at a premium, such as "internet cafes", or hotel business centers, or classrooms. If it has decent media performance and is as quiet as they suggest it is, it might make a good media PC for the living room. But I can't really see it becoming my primary desktop PC, either.