From a mathematical perspective, those in Finance can clearly show you how not being diversified -- in an economy that allows for diversification -- is not prudent. Why isn't it prudent? Because, for most investors, not having all of their eggs in one basket will prevent them from devastating loss should some baskets break. Baskets break all the time.
Although diversification is an ancient concept, the modern idea of financial diversification in the context of creating an effective investment portfolio can be attributed to Harry Markowitz. Markowitz published his seminal paper titled Portfolio Selection in 1952. Check it out here, and other places online.
Some investors, however, feel that they don't need this rule. Some investors think the rule, or more precisely, the nature of the world in the investing space, doesn't apply to them. They feel that they know more than the typical investor or investing firm knows - they think they're somehow better at picking stocks or making investment decisions. These people -- and they are everywhere -- believe that they're just different. It's a common thing in humanity, and it might not change.
And now, given the rise of cyrptocurrencies and crypto assets to quasi-mainstream financial assets, we're dedicated to providing quality, relevant, and interesting material on cryptocurrencies and cryptoassets. Articles on Bitcoin, Ethereum, Ripple, Cardano, and many more cryptocurrencies and cryptoassets can be found on Pennies and Pounds - all that in addition to a plethora of information on what cryptoassets are, how the entire crypto industry came to be, blockchain/immutable ledger technology, mining, proof of work, proof of stake, and how to prudently invest in crypto if you are so inclined (based on your risk tolerance and ability to withstand the volatility that will come with a crypto portfolio).