Some time ago, there was a question about splitting the crank case. I just pulled one apart. FWIW, the right side has a conventional ball bearing, and takes a bit of bashing with a soft mallet to get the crank out of.
The left side uses a roller bering. So, if I were to do this again, I'd remove the left side case off first, because it slides off easily. Empty the innards, then tap the crank out of the right side case.
The logic is that aluminum expands much more/faster than steel. By using a roller bearing on the left, the crank can grow when warm and not side load the left bearing. The ball bearing on the right keeps the crank where is should be.
I did a similar mod on our Bultaco racer a few decades ago.
I believe the other reason was that the larger surface of the rollers allows more load, so the massive weight of the flywheel assembly doesn't murder the left bearing.

I hope I'm never glad I read that.

The disadvantage to that is the shifter.
Taking off the right, you don't have to mess with it at all.