His alternative to using BTC is using fiat money, which also has no intrinsic value. So calling out Bitcoin specifically for having no intrinsic value is unnecessary. He would have to clarify why exactly he believes that fiat money (the alternative) has any intrinsic value either.
What people also tend to forget is that USD for example is like 90% "crypto" currency as well.
A cryptocurrency is a more specific term, defined by the use of cryptography for security. The digital dollar is a digital currency but not a cryptocurrency.
But in order to create more Bitcoin you have to use quite a bit of energy to mine it, as it is also criticized by many.
I disagree with this point because mining BTC does not have an inherent cost. When mining gold, for example, you would have to spend a certain amount of money to mine it. This cost would not be affected by the price of gold.
The power and investment dedicated by BTC miners is determined by the price because the block reward stays constant (and the block time roughly constant). So the cost of mining doesn't give BTC any intrinsic value.
I'm also pretty sure that soon every top level investor is one way or another invested in cryptos.
I also find this unlikely. Buffet is very much a buy and hold investor - he buys things that are usually quite steady and holds them for a long time. Similarly, a lot of other investors would not be interested in getting involved.