My understanding is that electronic signatures are actually legally binding, and an electronic signature just means anything that signifies intent to sign (e.g. no crypto required). So the patent office accepts your name in slashes, as I recall.

Of course the real problem is that the organizations that require faxed signatures don't have any real idea as to why they're doing that or whether they need to do it or even whether it's legal, it's just "that's the way we've always done it"