I reluctantly signed up for a GMail account when I got my first Android phone--because I HAD to in order to really do anything, like install apps.
But I never use that address for anything. AND I only access it via my e-mail client, so even if I did choose to send mail to someone from that account (and I never have), it wouldn't pass through Google's hands. It goes directly from my computer, through my outgoing mail server (I have Earthlink) and to the recipient. The only incoming mail I ever receive at that address is from Google (like a receipt for a Play Store purchase).
People I know who do use their GM accounts for real mail, I try to encourage to stop using the GM interface and instead use a real e-mail client to send and receive mail.