Me and many people don't.

Just laptop is good enough. Although currently switched back to apple silicon ATM for LLM, price and convince reasons, and as soonest linux on Apple Silicon reach some maturity, will switch over completely.

However not using a smartphone is probably good for one's mental and physical healthy now days. It is understandable if your work require you to have one, but if I'm not getting paid, why would I even get a smartphone?

Back in the 80's there are investment people managing billions dollars and deals over pen paper and a land line!

Laptops are way heavier and more bulky than phones, and phones can do 90% of what a laptop can do across a cross section of most people’s daily tasks. You don’t have to be a genius to see the value in one. The mental health stuff is about social media apps and things, which aren’t mandatory.

If you don’t want one because of some principled stance that’s fine, but don’t pretend there’s no value in them.

I'm the opposite, I didn't own a personal computer from like 2015 until last year when I built a new gaming PC. I had a MacBook Pro from work of course, but I just got by on my phone / iPad for my personal life.

back in the 1880s, people didn't even need refrigerators!