I understand the preacher's concern about stability on bitcoin and cryptocurrency. However, all forms of investments are risky in nature. What I did not like about though is the sudden reminder of the love of money and greed. Crypto is not parallel to greed otherwise it should be equally true to other forms of investments (ie. MLM as you mentioned). Greed is when you abuse money or the income you receive.
Sad reality-people are quick to question the ability of something just because of one-sided information. He could have also asked those who are investing on crypto and not only get ideas out of people who does not believe on its capability.