Personally I wouldn't accept a signature made by mouse instead of a pen. How on Earth do you verify that? If you signed a cheque or voting form that way, it would be rejected. And I would reject it, too. I leave it otherwise to the receiver if they find a mouse scrawl the least bit acceptable.
It's much easier to get someone's legit signature than to verify the scrawl one makes with a mouse in its place. Need your city mayor's signature? Just Google it. Signatures show up everywhere. They're not as private as people tend to think they are. It's not as much of a concern, as long as you can provably deny a faked signature.
Having said that, I also would not use it to get someone to sign a document I sent them. I'd much rather you just autograph a piece of paper and hold it up to your monitor beside my document and take a picture with your cell phone. Yea, that's lame, but I'd trust it a whole lot more because there's (theoretically) no unrelated middle man, and a signature I could actually verify if I ever needed to.
I accept having to sign that way, but I don't like it. And because I don't like it, I won't ask anyone to sign something that way. What good is a chicken scratch that provably does not match the person's signature?