Yeh you need to do one on bikes with Integral ABS 1.Uasally on every service and everytime you go near the modulator(changing unit,changing fluid...)
It checks for air in the system,because the are 4 different circuits in the ABS system it is critcal the it is bleed 100%
Bleed tests are quite old,now they have moved on and call them a "Brake Check" which is alot more in depth.
As everyone knows BMW have had afew issues with the first gen Integral modulator,so the "Brake Check" is away to keep an eye on them at every service and posibly fix a fault or problem before they come a issue