Okay, I know we all have a tendency to side eye the “highly trained and qualified botanist Keiko O'Brien decides to become a school teacher” thing, and from an out of universe perspective it’s rather questionable.
But I love what it says about her character.
Think about her situation at the start of DS9. She’s just given up her position on the flagship so her husband can take a promotion that she fully believes he deserves, even though she’s not particularly happy about living on the station. There’s not much need for her specific skills where she is at the moment, and going off somewhere else to work would be counterproductive to trying to keep her family together.
But the moment she sees a need in her community, a need no one else had anticipated or even noticed, she automatically steps up and volunteers to fill it. She doesn’t go to Sisko and say “oh, this is a thing somebody should do”, she says “this should be done and I’m going to do it”. She takes on all the challenges and obstacles herself for something that isn’t even her primary passion just because it will help others. No one would have looked twice or blamed her if she had stopped when things go tough, but she fought tooth and nail to keep her school open because she truly believed in what she was doing.
(I also firmly believe that, if the school hadn’t eventually shut down, she would have found a replacement teacher and gone on to do her botany research anyway once the opportunity came up. The school was something that was needed, but her own role in running it was just a stopgap because no one else at the time was able or willing and it was better than doing nothing.)
tl;dr - Sisko may have had to bribe Quark into becoming a “community leader”, but he got Keiko O'Brien and her heart of gold and nerves of steel for free.