In particular the main value-add is that they have clients across so many different platforms, including most major bespoke smart TV brands[0], and their solution to streaming on WAN (HTTPS brokering) is pretty darn good for most people. Accessing my media from hotel rooms is pretty darn seamless, other than the wifi connection sometimes requiring downscaling to 720p or or so.
0: not really an issue nowadays with everyone moving to Big Tech-provided smart TV OS, but when you use an old TV with like mid-2010s webOS it's nice to see some old Plex app that still works.
You can do that with Jellyfin and Tailscale trivially on devices you own; for a hotel TV you can use a GL.iNet travel router (which will also let you access your LAN from any device connected to it) and it's all free (except for the router of course, that you just buy once).
Admittedly my use case is not the most common. For a number of what I think are well founded reasons I don't use the "smart TV" OSes built into any televisions I own, none of my TVs have the wifi password or access to the Internet. The HTPC screen is just a screen, something else that's smarter is driving it.
I also don't have any need for realtime transcoding as my home internet upstream speed is sufficient that I can watch 'full resolution' stuff remotely from my laptop or phone via VPN back to home office, and smbfs or sshfs access to the same file shares, without needing to use any CPU or GPU resources to process the video in realtime in between where it's stored any my client playback device.
I guess this applies to a relatively small subset of population who are always on the riad and travelling for work.
One must have a nightmare of a vacation to even consider turning on a tv in an hotel room, I can't even remember the last time an hotel TV served any other purpose than hanging a wet towel.