I think that I know what TSW is saying...
A side arm has to be 100% reliable, rugged, and as close to zero maintanance as you can get. It also has to have the right safety and comfortable carry size.
A pistol, on the other hand has to be accurate, attractive, and relatively low maintanance with good-excellent reliability.
For example, I have (for the moment) the 25th Anniversary 75B. I love it as a pistol; but would it be my side arm? No way! I would be too concerned about the glare offf of the shiny high-gloss nickle finish. I would also be too concerned with damaging that finish with a scratch or a chip. Poly guns (like the Glock, Sprinfield XD, CZ-100, ect...) do not have that problem. Take it in and out of the holster a few thousand times and no holster wear; you will never have to re-finish it.
You might want to have a differant trigger weight for a side arms over a gun that is only shooting targets. You would also probably look more closely at the safety system for a sidearm, possibly going for a de-cocker (the SP-01 Tactical has one, while the SP-01 does not).
What about size? A nice, heavy pistol at the range takes away recoil, but a light side arm is easy to carry all day. A pistol with a nice, grip that is comfortable in the hand might have to be sacrificed for concealability in a side arm.
You might have a super tricked-out pistol that is more accurate than you are, but every now and then there is a jam. A great range gun? Probably. A great side arm? No way!
A side arm will probably need night sights, while target sights would probably be best for a pistol.
I think you get the idea by now.