It can equal stronger climbing, but not necessarily better climbing.

The problem with being very strong is that you start to neglect technique, because if you can just power yourself to the next hold or through the move, why would you do it in a more technical way? Even if you try to be more technical, it can be very hard to get rid of the habit of powering through moves. This is something many climbers struggle with, including myself.

On the other hand, if you are a technical climber, but are weak in terms of physical strength, training your forearms can help quite a lot by balancing you out a little bit. So you would still have the technique that you have developed until now, and you would also just be physically stronger.

So I would say that it just depends on your current situation. Are you more technical, or are you more powerful?

What really helped me get better at sit starts was climbing on a moon board, and either finding boulders that have sit starts, or building new boulders with sit starts.

I was pretty bad at sit starts since they are very compressed for me, something I am fairly weak at. But after climbing for about a month almost only on the moon board, I really saw the improvement, and it was very noticeable.

I still work quite often on the moon board, and I can really see the difference from before and after. I try to do the most disgusting sit starts possible on the moon board, and I can do all of the sit starts on the regular route setting walls.

The moon board in my gym is a 30 degree angle I believe. If you don't have a moon board, I think you can probably do the same on any other system board.