Well, their reasoning is, free players have less hesitation to buy in teh c-store since they are saving money for a subscription and get used to it so eventually pay more then a subscription. That would be the ideal case for them.
Although even when FTP attracts 10 players that spend 5 bucks a month in their store that's better for them then 3 players spending 15 bucks on a monthly subscription.
Ah, yes, the C-Store. I forgot about that. Hopefully they'll clean up in the C-store, because I love this idea.