R2 is very slow
How slow?
I used R2 for a while, but I found it too slow. Around half of the targets are in the R slice (so they have long algorithms). And about a third of the targets in the L slice have a long setup move.
Sure, Old Pochmann uses more moves than R2. However, I think that because people use PLL a lot, they are much faster with those algorithms.
Learning R2 (just for the different algorithms) could be useful if you want to eventually use freestyle. However, I don't think you can be 'fast' and use only R2 corners.