Although, yes, this sounds absurd, it's worth noting that the TV licence pays for the BBC and the BBC has extensive radio (and web) offerings not only television.
Of course, that still doesn't make sense because to the best of my knowledge you don't need a license of any kind to listen to the radio.
Anyway, perhaps blind people want to listen to the TV. There are a lot of programs that could make sense even if you can hear but not see them.
I'm no fan of national broadcasters as a concept, but I have to say, the UK is excellent when it comes to audio description, much more so than any (English speaking) country I'm aware of. It's not just the BBC either, Sky and other private broadcasters also have relatively high standards.
For years, the only English AD you could get for extremely popular HBO shows, like Game of Thrones for example, were pirated British rips from Sky, as HBO famously refused to provide the service.
> you don't need a license of any kind to listen to the radio.
I believe you did once upon a time, but I guess they were phased out as TVs became more popular.
>The first supplementary licence fee for colour television was introduced in January 1968. Radio-only licences were abolished in February 1971 (along with the requirement for a separate licence for car radios).
Of course, that still doesn't make sense because to the best of my knowledge you don't need a license of any kind to listen to the radio.
Anyway, perhaps blind people want to listen to the TV. There are a lot of programs that could make sense even if you can hear but not see them.