Can you please explain why he is wrong
Where he wrong is in his appraisal of the idea of "intrinsic value".
First of all, no successful monetary medium has so called "intrinsic value" (which is a misnomer anyway). If it did, it wouldn't work as a monetary medium because it would quickly go out of circulation. (Although gold does not circulate as such - stays in vaults - its use today is almost exclusively as a monetary medium).
A successful monetary medium requires certain rare properties, such as resistance to counterfeiting, limited supply, fungibility etc. Once something is found that has those properties, it has the potential to be adopted and used in a monetary role by society. If so, it derives its value from serving in that role. And this brings us to the key point:
******** Items derive their value from their role - not the other way around *******
Here's some examples:
[1] - a plastic token at a fairground costs around 10,000% more than a similar plastic token in a hardware shop. The price difference is accounted for by the *monetary role* that the fairground plastic is playing. Intrinsic value of plastic tokens has nothing to do with it
[2] - a 1 km stretch of road built in the middle of a forest with 2 dead ends would be very expensive to build but would have no resale value because it could not function in a *transportation role*. i.e.
a) - 1 km of road which functions in a transport role = Very high value
b) - identical 1 km of road which didn't function in a transport role = Almost no value
The "intrinsic value" of the road, once again, has got nothing to do with it. It's the *role* the road is playing that's important.
[3] - Consider the value of gold from the perspective of the "Plastic Tokan" example at the fairground above. It follows that if gold did not have a monetary role in society, its value would be much less. i.e. it DERIVES ITS VALUE FROM PLAYING A MONETARY ROLE, not the other way around. Gold was the physical bitcoin of the day. It had properties which allowed it to function in a monetary role and that's what made its value increase. If not in a monetary role, the only other role that gold could have had was a utility one, where it would have had a much lower value. (There are plenty of utility substitutes both in Jewellery making and industry).
So Warren Buffet is potentially correct when he says that bitcoin has "no intrinsic value", but it doesn't matter. If it has the right properties to allow it to function in a "monetary role" then it will acquire a monetary value instead which will be extremely high. (And note: This doesn't even mean it has to be accepted at retail stores and airlines - gold isn't. It just has to play a similar monetary/store of value that gold does, except on an electronic trading platform).
To have understood that, Warren Buffet would have to think more like a systems analyst than an investment analyst. He would also have had to understand certain key technical aspects of cryptocurrencies and how much of a technological achievement it is to have developed an uncounterfeitable token which is transmittable peer-to-peer without the need for a counterparty such as a bank.
He's unlikely to be interested in those subtleties which explains the limited nature of his insights about Bitcoin's investability.