I think the FBI had no choice but to release the info today about the 'food card' arrest, given the rumor and speculation that's exploded on the internet with this case since day one. They know this arrest on it's own isn't important in the great scheme of things, as there are tons of such exchanges of money for cards every day, but can you imagine what would have transpired if they hadn't mentioned it right up front? It would have been a mess, their office would have been deluged with requests to find out more about it, and it would have taken valuable time away from their real investigation.
And I don't think a person talking on a cell phone is a big deal, regardless of her socioeconomic status. For all we know, it's a borrowed phone. Or one that was given to her. I really don't get into analyzing how a poor person spends what money they do have, and don't see any point to that. Everybody spends their money on different things, and a cell phone isn't necessarily an extravagant expense anyway.