Certificate authentication to access enterprise Wi-Fi networks is extremely common. Products like ClearPass exist for this exact use case. The “password” for a WiFi network (pre shared key) is an encryption key, not an authentication or authorization method, and is only typically used on small-scale personal networks.

This is completely separate from VPN which allows remote secured access to internal company networks. Certificate authentication to the network provides authentication, authorization, and accounting, as well as robust encryption of the wireless link.