I have used winders, motor drives, power boosters and battery grips on my cameras for as long as I can remember, for several reasons...
1. More power on tap and more shots per charge (or set of batteries, in the days before rechargeables became common).
2. More comfortable vertical shooting.
3. Better balance with larger/heavier lenses.
4. Many vintage film cameras simply didn't have any power film advance without a winder or drive, while others offered higher frame rate with a booster (EOS-3, 1V and 1N) or grip (some modern Nikon DSLRs have slower frame rate without).
The only "cons" I see are...
1. A bit more bulk and weight to lug around.
2. Twice as many batteries to maintain and charge.
If you don't like it, don't use it. I feel just the opposite. But I still am not a fan of "all in one" designs, with the vertical grip permanently built in (such as 1D series). I prefer a removeable grip/booster in case I want to shoot without it, though I rarely do.