My hearing is mostly OK though a little spotty especially when tired or otherwise not entirely paying attention. Some sound mixes make it quite hard to clearly make out voices in some situations, so I occasionally need subs for that. Also I sometimes watch TV while on the treadmill. Sometimes I prefer subtitles to headphones, especially with the noisy old treadmill I've got at home.

I also have some friends for whom English is a second or third language, despite being very good with the language generally they sometimes have trouble, for instance with strong accents or bad sound mixes, so find subtitles (in English) useful.