I'm going to say that, like many of you reading this will turn out to be, I'm exactly the sort of person who falls for deals like this. Sony are offering a deal on a handful of their digital games that is so tempting, such an incredibly intelligent piece of sales technique that I've already bought all the games on this list.
If you already own Hustle Kings, Top Darts or Motorstorm RC on PS3, congratulations – you already own a Vita game. People who own a copy of those games have a free version of the Vita game as well, meaning that you can get the trophy set on both PS3 and Vita (in the case of Motorstorm RC, that's two platinums for the price of one). This also works the other way around, if you buy one of those games for the Vita, you'll also get a copy on the PS3.
More than that, however, if you plan to get WipEout 2048 and own WipEout HD and it's DLC, Fury, on the PS3 (these were part of the Welcome Back package in Europe), then you'll get the whole thing as DLC for 2048 when it launches in a couple of month's time. DLC for Ultimate Marvel Vs Capcom will also be cross-compatible; one purchase gets you the additional characters on both consoles.
I can't imagine playing any of these games for hours and hours on the PS3 and then instantly switching to replaying on the Vita, so perhaps the deal isn't as amazing as it first seems. For what its worth though, it's still something they by no means needed to do, and the early supporters of the Vita seem to fully appreciate that. Here's hoping it's something they keep up throughout the rest of the PS3-Vita lifespan.