I agree, but the actual simplicity (no meta server etc.) is amazing.
I've found it to be incredibly reliable and low overhead. (I've been using for years for MySQL replication and docker across low latency WAN connections).
(I'm a bit confused which of tinc and zerotier in the parent post you're referring to....)
By "it", you mean tinc, correct?
I second that. It's one of those tools I keep coming back to. I've run production LDAP traffic through it, but also plenty of non-prod goofing around. It never let me down.