I made it because my friends and I use wireguard to have a private network, and they don't feel comfortable running a ssh server on their machines. It can also be used with a vpn provider like Mullvad without setting up a new nic or requiring special privs.
I want to point out a caveat to others: Proxifier != VPN
wireproxy's wg only forwards TCP and UDP. I am not sure how ICMP is handled. Other transports, though rarely used, won't be tunneled (and may leak, if not dropped).
Most importantly missing: DNS, which usually is handled over UDP (changing slowly now with DNS-over-HTTPS and some TCP resolvers). Without handling DNS requests via your proxy, you're still leaking information about yourself to the resolver you're using.
To clarify, UDP is not currently supported, but I intend to support it in the future. Incoming ICMP should be completely dropped, and outgoing ICMP is not supported.
One simple reason is that the serverside might not want to expose a shell to its clients, and instead just provide network connectivity; you can configure something like that with SSH, but it's a pain, and WireGuard is approximately as simple to set up as SSH, which is the primary reason it's so popular.
Is it a pain? As far as I know, all that's needed is to insert restrict,command="/sbin/nologin",port-forwarding before the user's key in authorized_keys. You can add more security by using a separate user, but individual Unix users for each client are not^W^Wshould not be necessary for security.