Why would a fast food restaurant not tell you about specials at the point of sale?

I went to Panera last weekend, for the first time in a long time. I’m a member of their club, whatever you call it. I haven’t been there in a long time partly because their prices went up but I was with my daughter and her two friends and their mom, and the kids wanted to go there so we went.

After I ordered our lunch (two bowls of soup, $10 each, which I think is expensive for fast food but whatever), I asked the cashier if I have any deals (which they can see on the computer, when I give my club card). She said no. Ok, so I paid the 20 dollars for two bowls of soup.

When I got home that night, reading my emails I saw an email from Panera that said “buy one, get one for $5. I was annoyed that there was nothing in the store that said “club members get buy one, get one $5” and nothing from when I entered my card at the cash register. The email was from the night before so the deal was present when I was present in the store.

Is there a reason you can think of why they wouldn’t have specials at the point of sale, and only on email?