I did it for a while - because I don't like using a phone for browsing or app-based stuff vs. in browser on my computer, don't like notifications telling me what to do, etc.

After a while I got a 'dumb' phone in case of emergencies.

Navigation is harder, but actually it's nice to navigate London with your head up, remembering things, and realising how two familiar areas you know distinctly are connected, etc. Not to say I never looked up a route before leaving home.

Ultimately it was WhatsApp for family that got me to buy a phone again.