The number one issue keeping institutions like pension funds and sovereign wealth funds from allocating assets into Bitcoin (BTC-USD) is ESG concern, says Kevin O'Leary, moderating a panel of Bitcoin miner CEOs: Fred Thiel of Marathon Patent (MARA), Jason Les of Riot Blockchain (RIOT), and Frank Holmes of Hive Blockchain (HVBTF).Holmes made an attempt at suggesting a two-tier system for Bitcoin, noting every single fresh coin he mines is pure - coming via renewable energy and was never used in any sort of suspect transaction. Needless to say, it wasn't a popular line with the attendees.Riot's Jason Les quickly took the opposite view, saying one of Bitcoin's strengths is its total and complete fungibility and that this must always be the case (to cheers from the crowd).Marathon's Thiel's sympathies clearly align with the fungibility argument, and he further notes that only about 900 bitcoin are mined each day. If institutional
