*facepalm*
This is nothing new. Blizzard is just offering the sevice instead of some korean 3rd party site.
eg:
http://d2items.com/?gclid=CJ-H-a33wqoCFQYnbAodF2_i4A#
Yes you have to be online to play the game. It's to combat piracy. Look at D2. Why buy it when you can DL it? Plus if you dont have an internet connection at this point in time chances are you don't know d3 even exists.
Worried about botters ruining the economy? Look at the D2 economy. Its still (mostly) fine. Relax.
No PVP? Well that sucks for some. I never played pvp so IDGAF.
Plus loot whores wont be a problem. You get your own loot from kills. So thats a bonus.