If any, it should rather follow /var syntax (local unless the -g switch is used). Else you'd break lots of scripts - the scripters assumed their binvars to unset self-acting.
/var executes /set -l not /set -u0 (which is what it executes now). Anyone who currently calls /bset is overwriting the value. Honestly it doesn't matter. Whichever. There's always the possibility that a change will break scripts. This is unavoidable.
