BTMs are good as a bridge between traditional fiat and crypto users and could work for different use cases.
people know how to use ATMs so the experience is already familiar and getting into crypto becomes less complicated for the normal non-tech person.
travelers might also use it for some quick emergency cash for example... they do!
or there might be a reason why you want to buy crypto quickly and there is no other method near you.
the fees are sometimes high but when you cash out using other methods online and then use a standard ATM they can be the same.
and western union is still more expensive.
sometimes BTMs can be even cheaper and faster to cash out crypto to fiat.
in case fiat disappears one day, BTMs still could be useful for other services, as paying bills or top-up for phones, games etc.
the technology of a BTM could still be useful to do payments on the go for any service.