The announcement of the new recommendation on daily low dose aspirin is very recent. The advice that I heard on not using aspirin to prevent clots with an afib episode is maybe 5 years old. I was told in 2015 to take full dose aspirin for a month after an episode. Noone says that now. Instead, they did an echo to check for clots after an episode. (I am not saying don't take it, and follow your own doc.)

From the web, explaining the different kinds of meds:
Anticoagulants such as heparin or warfarin (also called Coumadin) slow down your body's process of making clots. Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from clumping together to form a clot.

More:
The similar bleeding risk combined with the questionable effectiveness for reducing stroke risk means aspirin is not a good option for most AFib patients. While aspirin may not be an effective approach to reducing stroke risk in AFib patients, it may still be prescribed as a treatment for other heart conditions.