In my experience, a slow connection can be less usable for some apps than none at all.
If there’s no connection or you’re in airplane mode, some apps will let you access locally stored/cached data, but as soon as there’s a bad connection, they’ll wipe that data by trying to unsuccessfully refresh it from the server.
It's only usable for a limited number of sites that still work with most JS and images blocked (and of course no video ads). I doubt many tech illiterates are aware of how to constrain their data usage on the web or avoid AAA apps with obscene volumes of data transfer. Another issue is it's not just 2G but also heavily deprioritized.
This is an easy fix: Just cut off their data after it runs out instead of falling back to 2G speeds. Sounds like a win-win for both the data provider and the user.
Not sure if you are aware that with throttled 2G slow you can't even open a package tracking website these days, because the connection times out before you have downloaded all their asset dependencies. And those kind of websites do not support resumes of downloads (or partial content requests).
So you're stuck in a loop of not being able to use the web because the websites keep downloading stuff you don't need.