It makes no sense to me. If Musk is interested with cryptocurrencies, he should have setup a new startup dedicated with processing transactions from cryptocurrencies to fiat (he already has more than enough experience in the domain with PayPal) and facilitate the payment with crypto for Tesla (and other merchants).
Considering the high volatility of cryptocurrencies, including Bitcoin, and the massive amount of market manipulation going on, this is very risky.
Is it to find new revenues for Tesla to justify its absurd market capitalization?