I'm FI and mostly a passive investor nowadays but also still doing active trend following trading with a smaller percentage of our net worth.
I bought Bitcoin end of November 2020 at $18.500 per coin with about 8% of net worth when it was about to brake out to new all time highs ( I missed the complete 2017 run up caused by laziness of not following up on my own analysis).
In December 2020 I bought Ethereum (ETH) with the same approach (about to break out to new ATH in a super log trend with about 5% of net worth.
I wrote this article about it at that time:
https://freiheitsmaschine.com/bitcoin-2020-oder-die-blase-die-keine-war/ (in German)
Both trades are now 200-300% plus and I'm planning to hold both positions during most of 2021.
That said from a fundamental perspective I think MMM is wrong with his Bitcoin article.
What he (in my opinion) forgets to consider is the strength of the network effect.
Things have value because people are using them.
You could clone Facebook 1.000 times but they would not get any value without users (network) of the original Facebook. This existing network effect is a super strong moat. More users are still joining Facebook not because they like Mark Zuckerberg, but because everybody else is using it.
Bitcoin also has a huge network effect with more than hundred million users. This user base is constantly growing and no other blockchain project comes even close and will take that away.
Ethereum is another animal because its the leading platform for "world computer" applications (DeFi and NFT) and it has the by far biggest network effect in this area of technology.
I have no crystal ball but I speculate that Bitcoin could reach $150.000 per coin as "Gold 2.0" till end of 2021 before another bear market starts. This would represent a market capitalization of about 3 Trillion or just below 30% of the market cap of Gold.
Ethereum could reach about $9.000 per coin till end of 2021 which would be a 1 Trillion market cap or 50% of Apple stock.
Could this be wrong? Of course.
But there is a significant chance that both speculations are playing out because the majority of people still don't understand them or the reason why they have value.
Initially I risked about 12% of net worth and if both speculations would have instantly dropped to zero, it would have been painful, but we would still have been FI.
I both speculations play out like I estimate they would double our family net worth after tax. (crypto gains are tax free in Germany after 12 month holding period)
That's a pretty good bet in my opinion and a maybe once in a decade opportunity.
Have a nice day