I used 32 minutes on my mobile phone last month to land lines from 7AM to 7PM last month. A ridiculously low number, until I saw that I used 6 minutes to landlines in the 7PM to 7AM window.
I have unlimited mobile to mobile (regardless of carrier), but I used 600 mobile to mobile minutes last month, which is below my 2 year average of 732, and continuing a downward trend.
I sent 5783 text messages last month, continuing an upward trend.
I used 2.6GB of data last month, also continuing an upward trend.
My cell phone company is really an ISP for me.
I point this out for this: Assuming I could VOIP with a Google Voice number, if I switched from a mobile phone to a 4G tablet with text capabilities, would anybody really notice?