Hi Danran,
It is explained here, in the first paragraph;
https://openvpn.net/vpn-server-resources/create-connection-profiles-and-connect-client-installers/
Basically the server-locked profile is universal and isn't locked to a particular user account. It does this by referencing an API which the client must support. Therefore the server-locked profile isn't necessarily compatible with all OpenVPN clients. The user-locked profile is but it's locked to one particular user account.
Kind regards,
Johan