I absolutely agree. Though others may chime in about it ravaging your battery life. Still, the ubiquity of wifi these days is greater than that of USB tethering, BT DUN, or BT PAN. IMO, it's easier, and more likely, that you'll be able to get your devices to talk to your N900 if it's acting as an access point, than through the other methods.

There just needs to be a "low power wifi" mode that's more commonly implemented. Something where all of the devices involved only expect to be within 1-2 meters of each other. That would probably help the battery life issue quite a bit.