I keep hoping they will help address non-Internet TLS. For example if you run a HTPC, fridge, printer, device controller or anything similar on your LAN and want to talk to it over the same LAN using TLS. Getting a workable cert is currently not possible: for example the LAN names aren't going to be unique. Plex did solve this in conjunction with a certificate authority, but that solution only works for them. The gen…
The Plex approach would be possible with Let's Encrypt, though you would have to find a way to avoid running into rate limits (via PSL or by making users use their own domains, which is admittedly only an argument if you're catering to a technical audience).
[1]: https://cabforum.org/wp-content/uploads/Guidance-Deprecated-...