I've stashed about 50 boxes of Boge and Smok cartos, and approx. 15 carto tanks. Only 1 tank is a Phiniac. The rest were all $2.50-12 on sale or clearance. I figure they're insurance in case of emergency, when I can't build coils, and/or run out of my factory coils, but I still want to still vape.
People do still regularly use them, and some even still use them exclusively! I've helped source cartos for several people on ECF who've had problems finding them at reasonable prices. Many vendors who still have any want an arm and a leg for them because they're fairly scarce. Sent some free Evod Glass tanks & coils to several people, to maybe gently nudge them to at least a very basic clearomizer that's inexpensive, still available, easy to use, and takes cheap readily available coils. All have said they really like them and use them, but still love and prefer to use cartos and tanks!