The big difference is in the plastic you can use. All these boats are made of polyethylene (PE). PE molecules are chains of ethylene monomers, where the length of the chain determines the physical properties. As the PE molecule gets longer, the plastic gets harder, the tensile strength goes up and it gets tougher. The molten plastic that's molded also gets more viscous.
The blow molding process works with high pressure, so it can use a more viscous melt than can rotomolding, which relies on centrifugal forces and gravity. So blowmolding can use a higher density PE, with longer molecular chains that results in harder (wear resistant), tougher (impact resistant) material. The downside is that the molds are way more expensive, so you can't do design turns as often.
I've a suggestion to keep you all occupied...learn to swim!