That amphibious scooter is a bad compromise just like this amphibious airplane I used to own. Lousy boat, poor airplane.
What was the take off run from the water? The airport where I learned to fly had a couple of those.
Maybe I have maintained enough boats to have this opinion, but, before and after your party there is a lot more work to a boat. If it's a party you want you don't need a boat, you can just invite people over to your house. Funny, I ran into a guy I know at the local BMW dealer a couple of weeks ago, he publishes a boating magazine. I mentioned the idea that motorcycles were easier to enjoy then boats, he agreed. He also raced motorcycles for many years and published a motorcycle magazine before getting into boats.Hmmmm, not sure about that. A lot easier to party on a boat...and you don't even have to leave the dock.
Although, for sure a bike is easier to own.
Plus, to use the boat you have to hook the trailer to the (Expensive) tow vehicle, then tow it to the ramp,( sometimes paying ramp fee) go for ride then haul it out again, or drive to the marina (very expensive), hope the tide is high ( so as not to go aground) or maybe low ( to get under bridge) then hope fuel dock is open and has fuel, wait for sport fisherman to fuel all two hundred gallons into his tank, etc. etc. etc.. Much easier to enjoy a motorcycle.