I've never used it or saw the point of it tbh.
I'm showing my age here, but in the days before smart phones, ipads, tablets, etc. and going back even further, the internet, it was seen as a vital service, and I expect it was regularly used by a large proportion of people who had access to it (bearing in mind not all TVs supported teletext services).
There will be people now who have grown up in the internet age, who have probably never even used it, which will be a reason for decline in use, and therefore closure, which has been happening over recent years with the closure of teletext services by most (if not all) other broadcasters in the UK.