empty perfume bottles on ebay

Noticed people selling empty perfume bottles on eBay.. and people are bidding! Spotted one a while back on L'Occitane Fleur Cherie empty bottle. Anyone know why?

Some of them are a work of art. Maybe they are limited editions.

I have a friend who used to collect perfume bottles, didn't care about the liquid inside it. Jean Paul Gaulter ones her favourite as they came out with slightly different flankers(this is a lighter,summer version), some released only in the Far East etc. So the bottles had variousions (sp) and that is what she went for. Perfume bottle collecting is really big, they have their own forums, newsletters etc.

Of course, some well known sellers buy empties fill them up with fake juice and sell as vintage whatever.