Just as I checked your message, I checked my Atmos Rewards account and Alaska credited it. They say it can take up to 60 days...so fair enough.
But yeah, back to the topic about Delta - while Delta does not reward miles for the flight itself, if you buy a seat 7 days before the departure (which I am not sure whether it's still possible now that the rules were modified a bit compared to when I purchased the ticket), you'll still get some miles. I earned an extra 107 miles that way, and that's without having any Delta credit cards.

Idk if buying for a bag will gain miles too.