I don't use it (or need it) myself, but when I was working for a sporting equipment manufacturer a number of years ago, every salesman had a cellular dongle for their laptop. We had to remind them they had direct ethernet connections when they were in the office.

Fun fact, I once bought a reconditionned laptop and the sim card of the previous owner was still on the slot. More interestingly I could use it to connect to the mobile network for at least 2 years without even knowing the PIN (and having reinstalled to linux).

Do people really not use it? I use my iPad cellular all the time. Constantly.

One of these days I'm going to buy one of those old MS Surfaces with cellular and stick Linux on it. But for the installation/drivers hassles I'd have already done so.

Coming soon to Macbooks, now that Apple's in-house modem removes the need to give Qualcomm a percentage of retail sales price.

iPads offer $2/GB prepaid US data via eSIM.