Would you want to release an NTSC disc in a PAL territory, knowing that a proportion of your customers wouldn't be able to play it? Or, worse, that there'd be complaints from angry customers? Most large displays made in the last ten years can probably handle NTSC, but a lot of smaller sets can't, and a lot of people have sets that are much older than that! It's certainly not something you could count on!Originally Posted by Brian Borst
Not all older European sets can handle NTSC. Every new one can, so most people (except if you have an older television, of course) would be all right if the extra material is in NTSC.
There are a few NTSC titles on sale in the UK, and they're usually prominently marked as such, to avoid problems.
Of course, technically it's best if Blu-ray SD bonus features are encoded in their native format, wherever possible. That probably means NTSC in most cases (certainly most material on discs released by the Hollywood studios will have been mastered in NTSC).