"While I love Bitcoin, Ethereum is better because it builds contracts into the same blockchain, which creates greater functionality. "
A very interesting statement and one many agree with. The potential for ethereum might be greater than bitcoin.
Will holding BTC or ETH in an IRA be commonplace in the future? Perhaps. My feeling is the governments of the world are going to be so far behind the proverbial 8 ball on crypto that it matters little.
Your right governments will always try to figure out ways to control, tax and regulate.