It is. I am not sure the exact answer myself. However I suspect there is a worst case condition if you make square wave using BCM bits. Generally speaking it never matters. However it can cause issues. I am curious if Louis knows or has experimented with this.
My thinking is FPS times Multiplex times BCM bits divided by 2 represents worst frequency for PSU. Standard PWM is BCM bits divided by two times better, however is computationally very hard. For most of the use cases this never matters for BCM. This avoids need for expensive hardware and other stuff.
I also have reasons to suspect another trade off exists in multiplex and bits of depth in terms of current/brightness division for LEDs. Regardless of CIE1931 or perceptive brightness. This would not hold for outdoor panels of course which have more than higher density panels using more multiplexing.
Edit: Outdoor panels generally force longer chains which improves the PSU frequency. For the same number of pixels you increase the columns rather than the multiplex. The lower multiplex improves current/brightness per pixel. This does increase the load but lowers the frequency on the PSU.
In a more realistic usage the frequency will not be this extreme. However it can be. Bulk and/or decoupling caps can be used to average the power draw into a larger lower frequency load for PSU. This is again outside my wheelhouse but I know some consideration is required.