interruptor work with the cable running uninterrupted, the housing is spread..
but a brake lever made to be at the end of the cable lets the pull always be straight.
not flexing the stiffer part where the end of the cable is soldered/molded on.. which can promote metal fatigue..
the flexing that end is not good, that is why brake lever designers let the pull remain straight..
A work around could be use a 3~4cm long piece of housing on the cable head end, butting into the lever seat,
so the rest of the cable which has not been soldered stiff , is flexed.. where it remains flexible..
....