-If you use your google voice as your default number (and don't use your carriers number) then you can just set it up so that all calls are routed through GV.
-If you use google voice to call some people and your default number (ATT/Verizon...) for others then you can make a list in voice choice. "Call these people using __________ (google/default), call everybody else using the other."
-If you don't use your google voice number for anything, there is no reason to have voice choice (in my humble opinion)
If you just want to just use your primary (sprint/ATT/Verizon) number you can
1. Turn voice choice off (in settings)
2. Uninstall voice choice
Cheers
C