When Mike Caldwell released the first Casascius coins in 2011, the idea was simply to prove a concept (tangible bitcoin), and provide another means to get people interested in bitcoin. They were intended to be given away, or carried around as conversation starters. I did both, and they worked very well. The coins I gave out as stocking stuffers got several family members interested in bitcoin, and for a year or two, I always had a Casascius coin in my wallet, ready to pull out when some gold-bug complained that you can't touch bitcoin.
Obviously Casascius coins are now rare collectors' items, especially since the FinCEN threats caused Mike to shut down.
To people complaining about the premiums on these coins: they are fascinating remnants of bitcoin's early history; both the original intent and why they are no longer produced are intimately tied to bitcoin's character. Such things tend to be valued by people; we are creatures of nostalgia and many of us have the collector gene. For comparison, look at the premiums on some gold coins that only had a mintage in the hundreds... They may be worth $1000 in gold value, but many of those coins can sell for 5 or 6 figures due to rarity value and/or historical significance. Calculate the premium percentage on those....sheesh.
Anyways, Mike produced beautiful coins, which helped me, at least, generate interest in bitcoin in the (relatively) early days. I hope, and expect, that their collector value will continue to be significant as time goes by.
the 1btc error coin was going for 3X or more in 2013.
i used to have a 1btc to fiddle/play around with when they were cheaper, but stopped touching them ever since the last spike in price.