One reason to concentrate miles and points is if you travel enough to make elite status. Of course, the holy grail is upgrades, but expedited check-in, special boarding, etc. are nothing to sneeze at if you travel a lot. Time IS money and these things save time.

That being said, there's a difference between being smart and being obsessed. I have a preferred airline (C0) and hotel program (HH). These are based on my travel patterns and preferences. If they are close on price, I'll use them, if not then I use something else. That's my $.02.