As somebody who made a poster for an event just few days ago... I find it funny that this probably took just as long as without AI while probably going through a less rewarding process with little control and very limited learning.

A non professional design would probably take few hours doing it the very first time, discovering the software to do it, maybe learn some shortcuts, few key principles e.g. using a background then putting things above, etc. The next time though they would probably take 30min with a better result, the time after that maybe 5min with complete control.

It's really not such a demanding process if you rely on existing building block, namely dedicated software, assets like imagine banks, fonts, etc.