Blue Basic hasn't changed but the next tier (Blue) has. It used to include a checked bag and since the fare was a little less than the bag fee I always went with that one (Blue). Now it only gets you to be able to select your seat when booking. I never paid for one bag each before.

After booking a new flight last week I called them and they confirmed that it was changed and you need the JetBlue + credit card to get the checked bag allowance. It is definitely worth it as mentioned above