Here in the US I think the killer app is breaking the local cable company’s monopoly on providing high speed internet to the home.
FWA is a spotty solution anyway. Economically it works best in the ‘WebPass model’ where you server a whole apartment building in an urban area that has a clear line of site.
Rural carriers are averse to maintaining their copper networks, never mind installing fiber. If you are fortunate you have a line of site to a tower but probably you are less fortunate. When you head south from Ithaca, NY you encounter a dissected plateau at an altitude around 2000 feet. There is no ‘highest hill’. A tower on one ridge can sorta see into the immediately adjacent valleys (though the sides may be steep enough to still make shadows) and under 1 GHz maybe into the next valleys over. Heading South down to Alabama the mountains get bigger but it is basically the same story, where FWA goes to die. It is delusional that it could be cost-effective or even effective universally because in a lot of cases there isn’t even a road or a power line at the top of the ridge.
FWA really does create competition for people where geography is favorable but it is no answer for the many people still stuck with slow DSL.
My rural area is served by an independent telco/ISP. They would agree with the part about maintaining copper, but installing fiber has actually been their solution due to the lower cost of ownership over the long term. I wish more carriers saw it that way.