What To Work On is your personalised practice plan for the short to medium term. It's driven not by what areas of your game are weakest, but what areas are most important to you scoring well. So for you, it looks like when you putt well, you score well. Therefore you want to maintain/develop that level of skill otherwise your scoring will drop.
A great way to think about it is if you have a player who is consistently not good OTT, whilst they may want to improve, it doesn't really effect their scoring because it's consistently not good and therefore the WTWO percentage would be lower. However, if that player has days where their PUTT is exceptional, meaning they score better, but also days where it's not good so they score worse, their PUTT importance percentage will be higher. Even though on the whole, they may be a better putter than driver.
Where this is different to Strokes Gained is that SG only tells you what's bad and what's good. Not what really effects your scoring.
What we would say is that for the long term, of course you want the lowest scoring part of your game to improve, so don't ignore it. It's just not that important to your scoring right now.
Hope that helps but just shout if not.