I've played online now and then for about 10 years. For me, the biggest difference was the addition of phantom events. Unlike normal online tournements, where you have to buy some packs to paticipate, with phantom events you just pay a price. In return you don't get to keep the cards you play with.

For people just looking to play, not to compete or build a collection, phantom events make way more sense. I have to imagine their popularity has also depressed the secondary value of packs.