1- It's not meant to spam the front page. although once new features where you can filter or subscribe to different tags will be implemented it will not be a problem.
2- It should have like I wrote a dedicated whale or dolphin user to up vote and put some money in the pot. so no begging for up vote needed.
3- there is no way to limit those kind of posts under the betting tag for example but once one bookmaker will show good reputation of payments it can be limited to few bets a day not dozens.

and I don't follow your "play of the day" idea. you mean predictions ? if so it cab be parallel to the bets opened.