Others pointed this out already, but I'd like to second the simplicity. It's much, much easier to set up wireguard, especially compared to the mess that is openvpn. I had to use algo to set up openvpn originally, and God help you if you're not on ubuntu.

Secondly, wireguard is faster. If you're dealing with lots of users, CPU could be limited; in such environments, wireguard has allowed me up to fifty percent more throughput than with openvpn. It's also newer and probably not as optimized, so may get better. Finally, the new tap/tun driver on windows is orders of magnitude better than the openvpn one.