If you only bought them, you do not need to do anything.
However, if you earned or mined them, they are treated as income at the fair value or their daily price
You must confirm it from a local CA
There are no time limits. You would need to refile past years if you had income to declare.
and even if the amount is pretty high , you are not liable to pay tax since you didn't make any profit
You would definitely want to declare that, as you have $70,000 capital losses you can offset against other gains and a portion of your income. That's a $27k tax rebate (albeit over many years).
These aren't new laws, they are clarifying existing ones, so they are retrospective.