You might not, but most people would if that's all they did. And this would affect Blizz' bottom line.
Like me. I'm the perfect example of this, Ben. Honestly, I was bored. . . and now I'm still playing.... >.<
Plenty of people may pay two monthly fees, but most won't. It's a question of: "Are there more players paying for two accounts, or more people who DON'T or WON'T have two accounts, but would get added longevity from their current subscriptions by playing both factions?". And it's the latter - most people don't love this game enough to purchase 2 accounts, but would play for longer if their horizons were broadened.
Plus, it broadens the social aspect of the game in more than just a "/ragelog -> Hey quit ganking me, douche" kinda way. For example, my buddy from work who has a bajillion Level 80 Horde toons just made an Alliance toon, as well. Now, I can run his Alliance character and power level it, then switch factions and he can do the same for my Horde. He sure as hell wasn't gonna pay to transfer and or faction change all of those, or for a second account, and neither was I. But now he's in FP, and there's an entirely new network of people for him. It'll take months for him to level and gear another toon, then he can PVP against Horde for the first time. Like this, last night: "[G][12-Saevio]: Chris just ganked me... -_-" And that's awesome; i mean who wouldn't wanna gank Coeus if given the chance?
Milking the current subscriptions instead of expecting people to purchase two -- smart MOOve, imo!
