I reckon it's because the BWP usually can retain at least 4 mapping programmes at different hertz levels. The BTE has only 2 programmes, but I ain't too fussed about it because the BTE does a fantastic job, just about the same as BWPs.
I found it annoying wearing the BWP because of the cord - constantly stuck onto my skin on my back whenever I sweated at work. It also got jerked about by clients who constantly needed physical assistance. (group home for the intellectually disabled deafblind individuals)
