Benefits of Belt Drives for Steppers

[m_c]

Like a lot of things, people use something just because others have used something, but as you've realised, that doesn't mean it's the best something.

However it looks like you've only considered torque, which is only one part of the equation.
You also need to consider inertia and acceleration.

Ultimately what is best, depends on balancing acceleration, maximum speed, accuracy, and any physical constraints (i.e. where the motors are going to mount).


Another thing is don't rely on microstepping for accuracy. When microstepping, the motor position is essentially balanced between two electromagnet springs, so load can push it off the microstep position. I'd personally base accuracy around full steps, but half step accuracy is still a reasonable assumption.