As a CA(Certificate Authority), Let's Encrypt provides free and automatic TLS/SSL certificates, thereby enabling encrypted HTTPS for SRS Droplet. It's very easy to use, only by 1-Click.
HTTPS is required for publishing streams using WebRTC, and it adds security. If you want to use the video streaming in any HTTPS website, such as a WordPress website, you must use HLS/FLV/WebRTC with HTTPS, or it fails for security reasons.
Note that SRS droplet only supports a single domain name, which makes the problem simple, and easy to use.