IMO, if there's no lift or canopy it's not worth it to me. You'd have to pull the boat out every few weeks to prevent blistering as stated before and wash the underside because lake/river grime and crap will accumulate. The sun will be hard on your cover and gel that is visible. Plus you have to lug your stuff each time to the boat anyways, and if you have speakers/stereo equipment then there's always the chance for theft.

Up to you, different pro's/con's.