Yeah its an idea to try. I doubt it is going to bring much money at all. The amount of eyes on Steemit isn't that much.
The only obvious type of ads that would maybe work would be crypto related ads. Most of us use ad blockers so the ads will probably not be seen by most of the users of Steemit.com

I think a better solution would be for them to take a small percentage of post earning if you posted through the Steemit blog editor.
I think all the platforms should do that. They need to take a cut to reward their team and upgrade their platform.
I remember Dtube doing this , I think they may still.
Busy.org, esteem, parkio, and any other platform could take a slice of the earning.