Yes, me. But old modems? Two months ago I was integrating a 5G modem into a bare metal embedded application. AT is also used for the WiFi and Bluetooth chips/modems we use. AT commands on two- or four-wire RS232. Not everything is Linux and PCI/USB.
Same boat. A few years back I spent a summer living off LTE internet (before it was cool!) using a Sierra Wireless USB modem bodged into barely working with the help of pirated reference docs. Man am I glad that I gave up on that idea -- the OG AT protocol is, indeed, a totally obtuse crock of shit to the point where, honestly, it barely even qualifies for the moniker of "protocol" at all.
Same here, had a client ask for an AT command set to have a brand new nRF52 talking with a Cortex-M3 running some other legacy code.