"But your situation may only require this 4GB version and there wouldn't be a reason to spend more money buying bigger capacity."
If the person is a first time PlayStation Portable owner, then he/she is more than likely (assuming they only purchase PS Vita games) not going to need a whole lot of memory storage. However, if the person purchased a lot of games through PSN, they are going to need massive amounts of memory and lots of it. I think it was very self-serving of Sony to force customers to purchase a proprietary medium for storing PSN titles when they could've easily incorporated a microSD slot and have customers handle their storage in that manner. That could've been an easy persuasion for many people to purchase a PSV AND confidently purchase titles on PSN.