I feel like goal posts keep moving here.
I originally replied to a different guy because he appeared to be worried that this move would hurt AT&T's business. I don't see how it hurts AT&T as it looks like it will help them sell more phones.
You replied to my reply about how this could be bad for unlimited plan owners. I replied that I don't see that either since unlimited people can still buy new iPhones for cash or creative financing if they need monthly payments and preserve their unlimited deals.
Now you reply that this may drive traffic from Apple stores to AT&T stores and that accessory profits may be lost by Apple. First, I'm not sure Apple gives a hoot whether an iPhone is purchased at AT&T or Apple as they are going to get paid in full for that phone either way. There's probably some accounting math that shows that unit sales of iPhones sold and serviced by salespeople paid by other companies is more profitable than paying Apple employees for the same amount of selling & service time.
Second, there may be some merit to the concern about accessory sales. But it seems those accessories are going to be sold anyway. Every time I've been in an AT&T store, I've never personally noticed them stocking much in the way of accessories for iPhone. They probably do have some such stock but I haven't noticed. So yes, I suppose if an AT&T store happens to stock an iPhone accessory that a consumer wants to buy when they buy their new iPhone, they may buy it from AT&T, robbing Apple of the profits from getting to sell that accessory direct. But I'm sure Apple will be fine. For ever incarnation of that scenario playing out, there are probably at least the same number of scenarios of AT&T salespeople doing all of the showing work for consumers who then go to an Apple store (physical or online) to actually buy their new iPhone and any iPhone accessories.
Don't worry so much about Apple profitability. They are doing very well. VERY, VERY, VERY well. If AT&T accessory sales was a big threat to Apple profitability, Apple could stop/slow supply of new iPhones through the AT&T store channel.