I was at a bar in Brooklyn, NY last summer and was doing a public poll for my own entertainment to gauge sentiment.
I shit you not I asked about 300 people in the span of the day about Bitcoin. People from age 21-35 and only 3 people owned Bitcoin, and of those 3 only one had it in cold storage.
We are so early with Bitcoin itself it is no wonder why the Bitcoin collectibles space hasn't taken off yet.
I suspect it might be another 10 years before Casascius coins get any real traction.