I am not sure I understand your question,
4 wire switch does ONLY turn signal lights.
7 wire switch does the same but splits front and rear turn signals so brake lights can be incorporated.
YES, You can wire the 7-wire switch and not use the brake light circuit. You can also use the 7-wire with brake lights and add your additional turn signals as either turn only (wire them to come on with the front turn signals) or use as brake/turn (wire them to your rear turn signal/brake lights) .
