I’m sure there are those that would find having built-in cellular data functionality on their DAPs to be beneficial. Though I think the need for another data subscription (or adding a device/line to an existing one the way we already do for tablets etc.), and the want of a bigger than normal battery on the DAP might offset that a fair bit - premium DAPs tend to have shorter-than-I-really-want battery life as it is, are bigger than ideal, and are getting pretty heavy as-is.
For me personally, on the very rare occasions that I’m using a DAP and don’t have WiFi access but do have cellular data access, I just turn on the WiFi hot-spot on my phone and let the DAP stream from that. I literally don’t remember the last time I actually did that, though.
The only benefit to that I can see with a DAP having native cellular access is that you’re not draining your phone’s battery to use it. But then if you need to carry an additional battery/power-pack anyway then that doesn’t really get me anywhere.
And no, for me, the last thing I want on my DAP is phone functionality. Same with my cameras, while I think about it. One multi-purpose device is good - if I am going to carry more than one device it’ll be because beyond they’re task-specific and much better at that task than any multi-purpose device.
I’m sure I’m not typical here though - as my true “EDC” consists of my phone, my wallet, keys and AirPods. Everything else is situational and wouldn’t count as “every day” (even if it might be “more days than not”).