There is no point, unless you're serving data on the same network as said before. And even then you'd be better off with a switch that supported link aggregation then even using the wireless connection.
Wireless is insecure (especially when paired with massive-volume-transfer) and prone to noise (microwaves, etc).
You will see no difference on internet access. Check your modem's documentation, it will probably have a 100MB LAN port on it - you would have to saturate that connection* (you won't) to saturate a wireless network and you wouldn't saturate your wired network (unless you have some crazy setup with a hub).
*Well, 600 Mbits wireless N /800Mbits Fast Ethernet, but you get the idea, you still won't achieve that