Tailscale is just an added unnecessary external dependency layer (& security attack surface) on top of vanilla Wireguard. And in 2025 it's easier to run vanilla Wireguard than it's ever been.
Not only do you need to manually manage the keys for each device and make sure they're present in every other device's configuration, but plain Wireguard also cannot punch through NATs and firewalls without any open ports like Tailscale can, as far as I know.
Combine that with the fact that networking issues can be some of the hardest to diagnose and fix, and something like Tailscale becomes a no-brainer. If you prefer using plain Wireguard instead, that's fine, and I still use it too for some more specific use cases, but trying to argue that Tailscale is entirely unnecessary is just wrong.
Tailscale is great if it meets your requirements, & it probably does for most - I wasn't arguing that at all. Only that it won't be an option for everyone: in particular a non-tiny subset of home server hosters.