Lifesaving skis are good for going in and out of the surf, downwind and flat water paddling. However, for flat water, you will do a lot better with a ski with less rocker (less banana shape) ... and a lighter ski will be welcomed. For downwind, you will also find other surfskis to be a whole lot lighter, easier to catch runs, and just much faster.
It doesn't mean that the LS boats aren't good, they have a main purpose and they excel at it.
The short answer:
LS skis can be quite fun for DW paddling even though they are heavy, but they (in my opinion) provide nothing short of a horrible experience for flat water paddling. If you are not going through surf, and if you are not racing LS, you may very much want to go with a regular surfski.
Ludovic
(Brittany, France)