It’s really cool but it seems rather convoluted for the typical user. We should perhaps start making good use of the ID attribute and linking to that first before we start trying to use ~:text=
I agree you should prefer IDs but they aren't always available, and often using them is very convoluted for users (how many are going to know how to use the element inspector, or even what an ID is?).
I'm assuming Firefox has this context menu feature on the road map as well, though I suspect it will be a long time before Safari adds it just because Apple.
The average person doesn't even understand a URL at all—as far as they're concerned they're generated by computers for computers and are copied around with little regard for what the various components mean. This feature doesn't change that, it just gives a new way of creating a URL that does something slightly different.