There are currently around 750 English language subtitled shows around the UK every week, of the latest films, as listed here: (Google: subtitled cinema).
Subtitles on the cinema screen, for all to see. Although this is the preferred way to view cinema subtitles amongst most people that need them to enjoy a film, it requires cinemas to put on separate shows. Most people can't work their lives around one or two cinema shows a week, so currently, most people that would like to attend subtitled cinema shows can't do so. There's not enough choice of films and showtimes.
A 'personal' subtitle system, like the Sony specs mentioned, or seat mounted displays, like they have in the US, would give people a better choice of films and showtimes, which would of course result in more people attending the cinema, purchasing popcorn & drinks etc.
Derek Brandon