If I click on the 'use wan port as lan port' can the router/WAP have Local IP traffic data?

I have a wrt54gl as an access port, but it's in a remote location. It would be nice to see if it's local IP traffic or even it's general bandwidth usage. Is that possible if I connect to the WAN port and click 'use as lan port'?

Or does it lose all WAN functionality and become a dumb LAN port?