Re: [Auction | NO MINIMUM BID] The Times 03 Jan 2009 | 10% to FreeRoss.org
There's more than 8. For obvious reasons not everyone you ask will tell you they have one. If that was the way you deduced mintage and the $ amount people are willing to sell for than you would think only 3 or 4 casascius loaded 25btc coins exist. Not a lot of people are going to rush to tell a stranger they own something like that if you know what I mean 
Plenty must have been sold by the newspaper reselling sites from 2010/11 onwards who must've been wondering why that particular day was flying out the door.
And I'm sure there are a few retained by people for personal or sentimental reasons who have zero idea of what it can fetch. It'll be one of those things that'll be unthinkingly thrown out along with everything else when they croak.
Agreed unless professionally store where it looks like something that should be checked out for value it will be misconstrued as clutter