Well speaking as someone who's been self employed for over 25 years I'm not best placed to comment on what's currently taken for granted in the cushy parallel universe known as employed status.

Hence my question in the OP but I bow to all you employees if this case represents nothing new at all and wonder why it's in the news in that event.
Anyway, my understanding of the situation from what I briefly read was that anyone who falls sick
whilst on holiday (i.e.
during the holiday as opposed to say falling ill beforehand and that carryiing on during what would have been a period of annual leave) can now claim the time back. When I and my late wife were employees I don't recall any such concessions. In fact, in the 1990's, my wife was sadly forced to take a great deal of her annual leave when she was in fact sick for various reasons. Despite being employed by very large and highly respected international organisation there was no question of getting any of it back but of course things may have changed since then.
Whether it's a good thing is not really up to me to say but like so many of the workplace rules we see I can't help thinking that it must add to the burden on business at a time when the economic situation is perilous. Make no mistake it'd be great if employees could enjoy much better conditions and I can certainly see a case for someone who's off sick and can't therefore take the holiday they'd booked to be able to have the time for one at a later date but I also see the inherent problems with that as cited in THeNorm's post.
When we compare the rights our workers already enjoy as compared to those they're competing with in large parts of the world, I must say I cannot see how in the long term many of these can be sustainable even though it'd be great if the economic climate would allow rights to be enhanced.