multicast/mDNS is broken, and it doesn't seem that it will be fixed anytime soon. This prevents hosts discovering each other as if they were on non-virtual LAN.
Personally, I find that having to set up an OIDC provider is too much overhead for a VPN. In a corporate setting, you likely have something already, but for individuals or small teams it's too much extra work.
How could that work with their architecture? They configure your device to use a DNS server running locally in their app. That resolves their device names to their internal device IP addresses. Their device names default to hostnames, just like mDNS does.
So to give an example if I enter http://geder in my browser I want that to resolve to 100.100.5.10 regardless of if I am on my home network (where geder is) or if I am on a train.
From my perspective half the reason to use tailscale is that it replaces why I'd want mDNS with less bugs.
That requires rewriting all software to follow tailscale's model instead of mDNS. Additionally, discovery would no longer work when devices are on the same physical network.
Pretty much all of it is open-source, and there's a self-hosted open-source alternative available for the only closed-source cloud-hosted component[0] - and that's even actively being promoted by Tailscale![1]
