It depends how much money you have ..
If you have 'lots of money' - then it's a good way to store your excess to earn a good return, without effort.
Of course - if you have 'not so much' money - there are better uses like trading ..
In question of if it's going to drop .. The item itself has dropped a lot recently - but it seems fairly stable now .. I can't help feel as more people turn from drugs it may actually rise again ..