If you've got spare cash go for it but not required, it's more about the spot you pick to learn your waterstart. If you get the right location, good wind and shallow water you'll crack it in a day. Just buy a pool noodle it would cheaper, but what ever floats your boat.....err boom

Waterstarts are about technique and having your rig in the right position and using the wind to make it easy and if you fall, fall in the right position for an easy waterstart. I'd say even with that if you sank the clew your still going to have to swim it out, it may come up a bit quick but no much. Anyways it will hinder your duck gybes

have fun with it and let us know if it actually works.