I believe this is a Futures Backed ETF?

So can't see it becoming very popular - as will effectively have a 12-15% annual fee due to the cost of the futures rolls.
And if it gets to any size will hit the CME position limits (2000 contracts - 10k BTC - $600m).
https://www.cmegroup.com/market-regulation/position-limits.html

See:
https://bitcointalk.org/index.php?topic=5365787.0
for my logic for the 12%.