Um, no. They do full ID verification as well. If you pay for it.
My point stands, legally either a signature has to be notarized or it doesn't. If it doesn't, any signature can be effective. I'll agree that 3rd party hosting provides an element of independence, however, legally it's not required, and could be done by anyone. E.g., a self-hosting a solution that required the signer to upload a video of them clicking I AGREE would provide just as much certainty as anything Docusign can.
Of course, I also used https:/.opentimestamps.org to store the hash of our contract on bitcoin's block chain, because that way we both had proof that the contract existed in a certain form on that date. (I never needed that proof, because he was a good landlord, and I paid rent on time.)