Originally Posted by Trakhak

Oh dear. Picking up two wrenches instead of one.

Seriously:

Of course there's nothing inaccurate about using one crank arm or the other. I didn't suggest otherwise.

And: sure. Few bike enthusiasts have a shop-quality torque wrench capable of being used to set crank bolt torque lying around. But if you do, try using the two-wrench technique sometime.

In any event, as I said, it's faster and eliminates the need to grasp the (annoyingly short) off-side crank arm and is thus easier (especially now that I'm an elderly weakling). People who work in bike shops generally like discovering ways to make a task both faster and easier, with no downside.

I admit to feeling a bit proprietary about this discovery. It's a shame that so few people seem aware of it. And now it's the twilight of the two-bolt crankset era, so it's effectively obsolete anyway.