I've been using OpenVPN on my home pfSense box, it's working pretty good and didn't require I install anything except the OpenVPN app on my phone. Not sure if WireGuard has anything to offer that would motivate a switch.
A lot slicker in my experience. Instead of support everything it assumes both sides speak wireguard. Increases speed, reconnects faster etc.
...whether I'd break an existing setup for it...probably not.
Setting up Wireguard is actually quicker than refreshing your memory with the OpenVPN man page.
But other than that, there’s no big reason to switch if you have a setup you’re happy with.
Or maybe you do not care about the encryption, but care about the virtual and private part of VPN
There are many usecase. There is no one size fit all.
Only limitation is that it has to be UDP, Wireguard doesn’t support TCP.