I don't really like it when someone says "X is gambling". There many aspects of gambing. It is mathematical (mean, standard deviation, risks, rewards), social ("gambling = playing games", gambling ruining lives) and regulatory (how are financial risk vs. gambling risk regulated? what about gambling addiction?).

If "the house always wins" is gambling, then Bitcoin doesn't have a "house", and Bitcoin is more known for "I got lambo-rich because of Bitcoin" rather than "I lost everything because of Bitcoin".

If high standard deviation of payoffs is gambling, then trading forex with 100x leverage or betting your life savings on options is also gambling. There are also prediction markets and betting markets. Both can predict on same event, like Brexit. They seem to be regulated differently, but you can create a set risk-reward profile with a set combination of prediction market contracts, or place certain combinations of bets.

Saying "X is gambling" means something rhetorically, just like saying "Bitcoin is beanie babies". I have already written an article about Beanie Babies, guess gambling is next.

I take Warren Buffet seriously for investing strategies in general, but not his opinions on crypto.