Encryption 20 years ago was mainly used for banking transactions. You could have an ecommerce website and only the checkout would be encrypted. This is not the case today. Nearly all web traffic is encrypted; Let’s Encrypt helped make that happen.
Let’s Encrypt was started in 2012 with a goal of helping encrypt web traffic. From looking at Google’s Chrome’s HTTPS usage data, it appears that around 97% of traffic is now encrypted. While this isn’t all the doing of Let’s Encrypt, they most certainly had a hand in it.
This year Let’s Encrypt has issued over 300 million certs. This is 300 million sites that might other wise have their traffic communicate in plain text over the wire. Not sure if the 300 million is as impressive as the fact they have done it at no cost to the end user.
Another champion of this area is certbot. At first they made using Let’s Encrypt easier. Then they made using Let’s Encrypt pain free.
Stuck Cog also believes in encrypting traffic between connections. Stuck Cog uses Let’s Encrypt and certbot for managing SSL Certificates for hosted WordPress sites.