Parts...?
I've always wondered things like that. It's got to be for making more money or making sure the parts department has customers. My boat uses the manual VTS, which I love. My GTX is not equipped with VTS.
Back several years ago, all in line 4 cylinder, double overhead cam motorcycles were air cooled (I ridin motorcycles for many more years than PWC's). Then, in the early 80's, they started turning out water cooled engines. It was impossible to find the inline 4 without the radiator. I was so bummed because that had always been my fav motor. But, I told the dealer, I was not going to buy a motorcycle with an extra sub system, that wasn't needed. The inline 4 ran for many, many years without it, why add it? It was only an additional system you would have to take care of, buy parts for and if you were on the road and the thermostat or water pump failed, you were screwed.
This is what all manufactures seem to do. When something works well, just the way it's designed, they screw around with it, changing it because, the original design worked so well, they were not selling any repair parts.
Remember, these guys make a large chunk of change in service and parts. They are not going to design something that lasts. If so, they'll put their own distributers out of business. That's why the VTS is so screwed up and expensive. They need your money.......