Peck, I think the thing is that besides it just being quite rare is the type of collecting in this modern age (if you will).
Coins that we used to collect without much thought to cost are many times prohibitive now - I have gotten in the last 5 years maybe 6-8 coins in the late milled pre-decimal silver and copper series. I just can not "hang" with the buyers. On the other hand, I have always liked the Caribbean and used to live in Cyprus as a child so like some of the Br. colonial and commonwealth coins. As it turns out, some struck by the Franklin Mint were of awesome quality and a few actually released to circulation, so....
Beauty and rarity on them.
After the phasing down of operations at the FM, the Royal Mint took over [with varying degrees of success or failure] some of the contracts. In a few cases they appear to have utilised FM dies, and on others continued series and denominations of their own design. Quite honestly, these are IMHO much more interesting that modern Brit or USA coins.
Also, as with the case of the Trinidad and Tobago 1984FM 50c currency, it was hard to beat the combination of beauty, rarity and price ($3.59 incl. shipping) - this coin is close to unique although a few may be languishing here or there. Retrospectively, these are much more pleasing than almost ANY of my classical Vicky pieces.