Why would one buy a BTC for $490, when the price on US-regulated exchanges is $244?
The answer to this question is simple. The only advantage in buying this fund over buying BTC straight is the ability to purchase in your tax shielded accounts. Therefore, the logical explanation is that people are paying a premium to get exposure to tax free BTC gains. If you believe the price is headed to $10,000, you would much rather purchase at $500 without tax liabilities than to purchase at $250 with tax liabilities. That is the only logical explanation for the premium we are seeing.
Then we had to see these premiums on other funds too, like commodity or currency ETFs. E.g. I can put GLD easily into a tax shielded account, but not gold bullion. Nonetheless there is no premium on GLD.