Amusing item on eBay

I came across this rather amusing little item on eBay. It's certainly not the weirdest idea ever but I wonder how practical it would be to use.

http://cgi.ebay.co.uk/Sherlock-Holmes-Pen-Tom-Richmond-NEW-/150542362013?pt=UK_Home_Garden_PensPencils_WritingEquipment_SM&hash=item230d06259d