I often ditch my phone and carry my hotspot device for my internet. The only drawback is that for viewing my texts and OTPs i end up putting the sim in my phone or opening up the web interface on my laptop. This seems to work very well as a dumbphone per se.
This probably depends on your particular dongle model. Back in 3G era, some carriers offered USB modems with SMS locked out in the firmware, but you could flash a firmware from a different operator (also install their variant of software, the only difference being the added SMS tab and a different skin) and then you can text and even use USSD! (No calls, though.)
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