I haven't heard 'feature phones' since I used to read consumer electronics news sites (like Engadget, then This is my Next/The Verge) years ago.

I don't think anyone else uses the term; to the layman, they're 'dumb phones', to contrast with 'smart' (although increasinly 'smart phones' are just 'phones').

Or since those are American sites, perhaps it's actually a variation of regional colloquialisms.

Feature phones have capabilities beyond just making calls/sms but less capabilities than smart phones.

Yes, I understand it, I'm just saying I haven't heard anyone other than a consumer electronics journalist use the term. Everyone says 'dumb phone' (to mean the same thing) if the distinction is important.

"Flip phone" is another common term (for those that fold anyway.)