docusign? Maybe I'm just dumb, but I would definitely want a CYA third party keeping track of all legally binding agreements.
That said - Docusign has a moat because people are afraid (and CYA) by using them instead of anything else. To make an eSignature legal isn't really that complex, you just need hash based attribution, some timestamps and some ToS.
Replacing Docusign with something else is no where close to having an AI represent you in court