If you wanna share with friends and family; it's way more accessible than setting up access to a VPN/tailscale/etc.

There are not any alternatives that match every feature. The account system and number of platforms with a Plex app is unmatched. This matters when you share it with others who won't want to tinker with anything.

A media streaming system is a lot cheaper than the media. A lot of people bought Plex when it was a "buy once keep forever" payment model.