Not sure about the parent, but here's what I use it for:

A) easy access my other, older machines from my phone or work laptop to:

- self-host a Coolify server (a "vercel-lite" control panel)

- remote connect to my older laptop to run tests/longer coding tasks for work (e.g. large browser test suites, sandboxed claude running in bg to answer longer code questions, or build fire and forget spikes/experiments)

- control my home cinema remotely (remote+ app bc it's easy and Remote Desktop).

- use w. Mullvad VPN as an exit note (Tailscale has a really easy UI for it nowadays)

B) use it like ngrok to expose my dev servers to the internet (e.g. when sharing a quick demo/pairing with a coworker)

C) cheap NAS - I the old mac is connected to an external HD (the HD itself is archived to Hetzner)

I haven't (yet) tested it as an alternative to Hamachi (is it still a thing?) but I'm planing a LAN party with my brothers who live across the continent.

Like you, I also didn't know what the fuss was about, and I'm generally cautious not to get sidetracked.