I think this is a great solution:
1. Bluetooth was designed to use as little power as possible. My phones battery drains rapidly when I enable the 802.11 antenna while when only using bluetooth the power lasts longer.
2. The technology enables the use of an already existing hardware to facilitate more efficient transfers of data. Transferring over bluetooth for 15 minutes (when I transfer movie clips and such that IS how long it takes because USB synching sucks on my headset) will drain more power than transferring over wifi for a minute or less.
I think crowning it bluetooth 3 IS misleading though. Like someone else said, it should be called bluetooth 2+wifi
As a side note, I REALLY wish MS would re-enable their synching over bluetooth option. Their ActiveSynch used to have that option, but they disabled it due to security concerns... personally, I always have my bluetooth off if I'm not using it, so they took the feature away for people who are too lazy to set security on their devices.