When you look at the returns and losses of all these investments, the best was stockmarkets that gave average 2%. So bitcoin has given 700% yet people are complaining that it has been a bad investment, even though it is 350 times better than the next best investment. What other investment has given you 700% profit in one year?
Actually not only bitcoin has shown significant grow last year, me personally made a good money on ETH, XRP, STRAT and many others
altcoins which are not even on the first page of coinmarketcap.
I must admit that with bitcoin i made my first profit, and then i started to diversify it, and honestly that worked well for me.
As now i got more bitcoins as when i started my crypto journey, so most likely i will continue to do so.
Holding only bitcoin or ethereum doesn't seems that promising to me, i mean when you go all-in in one asset, this is highly risky thing to do.