Can you explain what TLS is? Everyone seems to be saying that it is important. But why? I don't get it.
The most common use of the acronym TLS is Transport Layer Security.  It is a cryptographic protocol designed to provide communications security over a computer network. 

TLS was proposed as an Internet Engineering Task Force (IETF) standard, first defined in 1999, and the current version is TLS 1.3, defined in August 2018. TLS builds on the now-deprecated SSL (Secure Sockets Layer) specifications (1994, 1995, 1996) developed by Netscape Communications for adding the HTTPS protocol to their Navigator web browser. 

The TLS protocol is important because it aims primarily to provide security, including privacy (confidentiality), integrity, and authenticity through the use of cryptography, such as the use of certificates, between two or more communicating computer applications. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securing HTTPS remains the most publicly visible.

Was this the meaning of TLS you were referring to?
Yes thank you!