The ability to stem the bleeding from an aggro deck by picking off their small creatures is something that white always struggles with, making this a perfect inclusion
In Japan, this card exploded in value, and the western release looked to follow that in a more controlled manner
For example, if you control Hallowed Fountain (a nonbasic land with the land types Plains and Island), Sunpetal Grove will enter untapped
Even with the best of support you are not playing this before turn three
Giving people a reason to come online and play on a regular basis is something that PTCGO had lacked originally
The tension of producing a strong mana advantage versus giving your opponent a Treasure creates many interesting decision points, and it gives the right deck a marvelously fast start by attacking well above its mana cost and helping you power out big threats