In the early days of the Internet, the idea of using it to send any kind of legally binding document for signature was addressed and given the technology available in those nascent days, summarily dismissed as not viable. There was simply no way to verify that the person who was using an e signature was who they claimed to be. With the new technology available including the use of a Certificate Authority to verify all information, the e signature is now considered just as legally binding as a pen and paper signature.
For the business world this has made life far less complicated and time consuming. Now it is possible to send a contract to a client via email, have them verify it, attach an e signature to it and return it in minutes. This makes far more sense than the days it used to take using the postal service or a parcel service and can be vital in time sensitive negotiations.