Bitcoin doesn't even have any of the above factors, how can it be said to be the best asset? These are just the views of bitcoin maximalists and they do not represent the rest of the world.
to be fair bitcoin is still among one of the best asset though, speaking about legality, so many country already approve bitcoin for investment, commodity or currency of spending.
from the perspective of safety and popularity, bitcoin is liquid enough for it to be considered safe investment because your money isn't gonna get trapped in a market that's illiquid and speaking about popularity, almost everyone know bitcoin nowaday, so bitcoin is definitely up there standing side to side with gold in my honest opinion, the volatility might be a problem for some people but for me it's nothing but an opportunity.
I personally still always prefer investing in bitcoin than gold, much more convenient for me speaking from experiences.
Yes, not many countries ban bitcoin anymore and it is becoming more and more popular. With a market capitalization of over $1 trillion and a trading volume of around $30-40 billion/day, there is arguably enough liquidity for everyone. But if we take those things and compare them to gold, bitcoin still cannot compare to gold. Gold has a market capitalization of up to 17 trillion dollars, gold is not only legalized but also a national reserve asset of every country globally...It can be seen that there is still a huge gap between gold and bitcoin.
For me, bitcoin is a big opportunity but also a big risk. So I just consider bitcoin as the best investment (return), not the best asset. Because as I said above, my standards for the best asset are different from everyone else, I wouldn't just look at the profit aspect and rush to judge it as the best asset.
By the way, I am investing most of my assets in bitcoin and only a small part in gold but I want to look at things in the most realistic and fair way, I am not living in illusions or fooling myself.