There are a few big benefits to eSignature software
• Your contracts are all in one place
• It's easy to make new ones / send them out
• You can see if the other person has opened it etc.
• It's easier for them to sign
As an individual it's hard to see the benefit of a lot of this software in your own life, just like it's hard to see the benefit of a lot of corporate IT tools to manage two computers at home. But if you have 100 contracts as a company (which is not very many), having an centralised storage function, an easy way to create new ones (say for bringing on a new customer or employee), and analytics that mean you're not asking "what happened to the ACME contract last week."
A lot of enterprise SaaS tools make it easy to organize things that are simple at a small scale, but become very difficult when you increase things by 10-1000x.