Almost did that myself once
[QUOTE=FarFarAway;3952952]Having GV on your own, regular phone gives the chance that breadcrumbs are left on it that could be found by someone more tech savvy than the SO. Also, I know of specific cases where someone had messaged w / a POT on his regular phone using GV, she called, he replied, but unbeknownst to him at the time, the return call came from his real # instead of the GV# - so the POT got his real cell phone #. Not good. I have heard that one can delete GV from one's phone when done w / it, then re-install it. This seems like a pain, and must involve re-entering info each time this is done.
I made the mistake described above, I am not really sure how it happened, but luckily I did it on my burner, not on my regular cell phone. It didn't really bother me that the POT had my regular burner # in addition to my GV #. She was a little puzzled about it, thought it made me look more like a scammer, but it didn't have any long-term negative consequences.[/QUOTE]All very true. Opsec requires awareness and care, regardless of whether you use a burner, an app or both. Each of us uses what works for and is comfortable for us based on our own situations and assessment of risks. There's no one "right" answer.