Hi, first of all we need to comprehend what he meant by "fling". This fling that he refers to is the current hysetria amongst investors who have least knowledge abt the technology involved and are only concerned with the huge profits which suddenly bombarded the traditional financial sector.
As per the report from Mangrove Capital on 200 ICOs revealed that ICOs provide an ROI of 1,320% as compared to 7-10 % in stocks. People like Eisman didnt have much option apart from stock trading before crypto currency hence its his new Girlfriend/fling.
Now coming to your question regarding what is the intrinsic value of crypto currency ? You can refer to as what was the motivation behind the inception of Bitcoin and Ethereum. Vitalik and Satoshi have already pressed upon the reason to provide financial freedom back to masses rather than leaving the power hold of finance/economy in a few hands.
P.S. - sorry for the long reply.