That seems really bad for accessibility and also many game engines don't let you disable mouse inputs on buttons easily (e.g. Godot). The mouse should be optional to accommodate people with accessibility problems.
I personally don't have any accessibility issues but I still think it's dumb to make the games harder to play for certain people for the sake of principle. Game jam constraints are meant to foster creativity, like the 4 colour rule, but this seems completely unnecessary. It is your jam though, so run it however you like.