For me, the biggest concern I would have is hitting something and shattering the hull. Not like fiberglass where you can repair it. Having said that, I have yet to hit anything with my fiberglass hull. Not like you go around bouncing off rocks and other boats a lot BUT if it happens can be expensive.
I totally agree with you, I came in too fast at puddingstone lake with my speedster 150 and put a hole a size of a quarter on my keel, it sucks, I fixed it up with marine tex it's great now, but I understand where you coming from.
But in the same lake and in the same conditions with my spark it would have been totally different, in that sense I would have actually reflected off of it. My spark has been incredibly durable. It's like those plastic kayaks you see.
Also, someone was selling complete hulls (including upper and Lower hulls everything) for $1500, so let's say for the sake of argument I did break my bottom hull, I could totally get a brand new bottom hull for under $900. That's unbelievable.
Also I took what you said in complete consideration, so for my insurance on my spark, I completely insured it for $5000 dollars, with a $250 deductible. It cost me $150 dollars a year.
So if I break the hull, I pay $250 I'm done, if I completely break the spark $250 I get a new spark, it's a win win situation for me all around.