That program looks kind of interesting but there are two things wrong with it:
1. I'd have to learn (and master) yet another dev environment, and one that is rather limited in scope. Plus if I knew Visual Basic (which it uses for game logic scripting) I'd probably just be coding my own games from scratch.
2. It doesn't build an .exe, which means only the niche Future Pinball users would be playing my game. I'd much rather be able to reach a wider audience, and casual players wouldn't be very willing to install a separate program just to run my table.