Is it just another way to part people with their hard earned?
Australians have had a long history with goat boaters and other various surf canoes with more efficient two bladed paddles. Though I haven't seen anyone going wussuping I imagine it would be pretty hard to do on an average Aussie beach break. I've seen pictures of people doing it on flat water and the first thing that comes into my mind is "that looks silly, a canoe would be much better"
Like a lot of things in life it is something you'll have to try to really know.
I SUP a old Windsurfer hull on flat water for exercise. Sure, it may look silly to some and it isn't the fastest way to get around, but it is pleasant to get out on the water and get away from life's problems for a while. It has only cost me $200 for a fibreglass/aluminium paddle. A canoe probably would be faster, but then that's another thing I'd have to buy. Plus SUP has a better view and you'll stay dryer too (except for your feet) which is more of a concern at this time of year.
As for falling in, it is hard to balance at times but the only time I ever fell (stepped) off the Windsurfer is when the fin hit something in the shallows. You'd be surprise how steadying a paddle can be.