Personally I have about 50% luck relaunching peaks. 2 of the last 3 times have been successful. After some 18 months of flying them almost exclusively.
I dropped my kite nose down in a "washing machine" river mouth bar the other day after an unintentional slight pinwheel spun the kite further than expecting. I was pulling those rear lines as soon as I could get my hands to them, before I even had water clear of my eyes. With fast reactions the kite leapt backwards off the water, spun when I released one, and flew up.
So, they aren't all bad at relaunching in the smaller sizes. Plus there is the factor that they will stay in the air in sparrow fart so you won't be having to relaunch unless you fly it into the water, or have a gear failure.
We kite in oceans a lot here and for various reasons all of the crew have swim ins. I get some ribbing for peak swim ins, but last time I was able to point out that everyone had also swum in recently, either with twin skins or inflatables, for various reasons (bowtie, line failure, wind too light to launch, wingtip tangle, twin skin foil sinking, etc). Having said that there's value in having an inflatable raft when all goes to poo.