Marathon Digital Holdings not only mines cryptos but also holds Bitcoins as part of its growing investment fund.The stock is appropriate for ESG-focused investors with its strategy to be carbon neutral by the end of 2022 but beware of short-term stock pull-back due to the energy crunch and supply issues.Bearing in mind accusations of fraudulent funding activities implying Bitcoin, I also focus on measures to ensure regulatory compliance.Compared with a peer, the miner should continue to improve on profitability metrics due to its particular financing model with rising production.The stock can rise further and is an alternative to owning an ETF like BITO which bears a high expense ratio, but also consider the risks.