Or even between phones with app stores / web browsers / sideloading, and those without.
A phone that comes with its own apps (like old flip-phones) but doesn’t offer any other extensibility, usually only has apps written by the manufacturer to support standard protocols like email and SMS, and no support for any company’s walled-garden social superstimulus factory. Even WAP was okay, since WAP only worked to deliver information, not interactive “experiences.”
(Admittedly, one of those apps could have been an IRC client, which would have been quite immersing. Luckily we never saw such from the manufacturers—they left that sort of thing to the J2ME sideloading ecosystem.)
Blackberries were smartphones. They had enumerable apps shoved into that tiny display, and keyboard model, but they still looked like flip-phones and lacked touch displays.
To me, the 'flip' is just a mechanical implementation detail. The real divide is smart phones versus dumb phones.