I agree that the pool means faster times, but smoothness is not always an issue. Currents are also sometimes a problem.

One of the main advantages of the pool is the turns.

OP says "deal with turns" but if you are a competitive swimmer, turns are supposed to make you go a lot faster.
If you look at 50 m times in short (25m) and long course (50m) pools (yes a 25m short course, not 25 yd) the long corurse times will be slower because you do not have the turn to speed you up.