burning fuse bits - is it worth a separate command in the menu?

pert:
Part of this is avoiding adding unnecessary UI elements.

That's a good argument.

You always have the option of using AVRDUDE directly.

Yes, and that's what I did on several occasions in the past, but since I found I can just do things from the menu, without checking the syntax of the command line arguments, I never bothered to go back that route again.