There are so many valid reasons to carry a phone and as per my post most of the time I do. I just prefer not to where possible. Like you though, not letting it rule me is the key focus.
It's amazing how quickly an entire industry sprung up around the smart phone. I mean do you remember back in 1985? Do you ever recall a person having their self-worth attached to their landline dial-phone back at home? Nope, not one. These days one is almost an outcast without the right brand of phone and woe to you if it's over a year old! Trillions of dollars revolve around a device that in around 20 years humanity seem to have gotten themselves addicted to...But we can all do without. It is what it is though and isn 't likely to change.
I'm content with my leave it home ethos although don't manage to do so as often as I like.