The wash sale rule applies to securities. Bitcoin is not a security; therefore, the wash sale rule does not apply to it. But other coins are considered to be securities, so the wash sale rule does apply to them. Also, OTC trusts, such as GBTC, BITW and OBTC, are securities and thus fall under the rule.
But all this is likely to be moot. The new tax bill has a provision that applies the wash sale rule to everything, whether they are securities or not.