"The delusion that we are like other people, or presently maybe, has to be smashed" This is the second part of the direction for step one in the big book. "Presently maybe" means some time in the future we may be able to drink, so you can see right there the goal is "permanent abstinence" another phrase used elsewhere in the book.
I can't reconcile that with the idea of staying sober "just for today". That idea seems to leave the door open for a future drink, and I have seen quite a few of it's practitioners demonstrate just that.
Living life one day at a time has quite a deep meaning to the alcoholic. The reality is that it is the only way one can live, yet the alcoholic mind is very prone to morbidly dwell in the past and insanely imagine a future full of fear or, at the other extreme, grand plans and designs, so much so that they forget to do anything with today, the only day that really counts.
AA has a 24 hour program built into the practice of steps 10 and 11. I am reminded of a passage from a poem. It went something like "yesterday's history, tomorrow's a mystery, but today, lived well, makes every yesterday a dream of happiness and every tomorrow a vision of hope." That is a good way to describe the AA philosophy of living one day at a time.