Hi,

using the wifi extension card in the P3 allows only communication with GHL Control Center; not any other access like GHL Connect is doable with it.
If you don't want to use ethernet, you can hookup a dedicated wifi accesspoint with an ethernet port an attach the P3 to it.
The wifi accesspoint can then be connected to your local wifi router, which allows you to use your smartphone and GHL Connect to access the P3.