Naw, most of us launch completely assembled.
It is easy enough to put up/take down the mast on the water, but during initial assembly, it's also easy to have the sheet line in the wrong place like under an aka or a rear bungee. It's not so easy to "walk around" to "clear the lines" while underway.
I do lower the mast at times before landing. One landing location is a small beach with trees overhead that just hit the top of the mast and it's easier if there is a shore break, or high tide to just take it down and bungee it to the two aka before coming in.
Also, I get the wheels out of the front hatch and assemble, then hop out in 2 feet of water to pop them under so I can roll up the beach to clear the way for others to land.