I've actually looked at that camera before for that purpose.
It's more pricey than I'd like. For $400 I lug my 7D around.
I had a similar thought. But I balanced that against the shots I would continue to miss because I didn't lug along the 7D and a lens or two, and also the fact that while expensive, it's cheaper than most of the lenses I'd want to use on a dSLR, and decided to get it.
SIdebar, but the final straw was a trip up to New Hampshire where we went on a family outing to some glacial caves, with names like "Eye of the Needle" and "Lemon Crush". I had a backpack with my 7D and 3 lenses in it, and came very, very close to getting irrevocably stuck in one of those caves! With the S95, I never have to say, hmmmm...should I really
bring along the 5DII or the 7D...it's going to be really inconvenient on this outing, but what shots will I miss without a camera, short of relying on my iPhone? The S95 produces some great images for it's size, especially once I started using DxO, which does a much better job at reducing the noise inherent to the smaller sensor, compared to DPP.
The other rationale for the S95 is as an emergency backup camera - most times when go out shooting, I am not taking both the 5DII and the 7D. If I'm on a long trip, what happens if the dSLR goes belly up? The S95 adds virtually no weight or bulk to the backpack full of camera gear, and gives me a backup camera, just in case.