Having better project generation features is a good idea.
But why on some web site? This is something that belongs into your build tool of choice, imho.
Extending on the features of sbt new¹ or bleep build new² would be imho the right way.
I guess building a kind of “Wizard” into the build tools wouldn’t be too difficult.
On the other hands side building a web-based Wizard that can generate at the same time projects for all the build tools out there would be more complex.
The other thing is of course: Websites and templates need to be kept up to date. Otherwise this looks really bad, indeed!
¹ sbt Reference Manual — sbt new and Templates
² Create new native build | Bleep