One thing I noted before was the bridging mode. Not sure if the native functionality or Tetherme do this because I haven't used it but MyWi allows you to bridge WiFi from WiFi. Why would anyone want to do this you may ask? Several reasons:
I ran into a situation just this last weekend where we were on the fringe of an available free WiFi hotspot. What I wanted to do was set my phone up closer to the hotspot and have my laptop (and kids iPod Touch) connect to MyWi. With the old version it could only have WiFi on either LAN or WAN and not both. The new bridging mode allows it to use WiFi for both LAN & WAN at the same time.
The next two are hotel related (in my experience). I've been in hotels that allowed free WiFi for mobile devices but charged an access fee for laptops. Not common but I've seen it a fair number of times. In this scenario I can tether WiFi to the phone and then WiFi upstream to their AP. The other hotel situation is if they charge for connectivity per device. Again, push the other connections through the phone instead of paying separately for them.
Yes, some may disagree with this from a morals standpoint, but to be honest, I've never agreed with those that charge $12 for people to check their email a couple of times during a one night stay. Screw them.