The entire cryptocurrency market follows bitcoin. When bitcoin goes on a bull run, the market goes on a bull run. When bitcoin dumps, the market dumps. Sure, there is the odd coin here or there which may suddenly double or triples in value over a day or two for no good reason, but selling your bitcoin to buy shitcoins in the hope that you get lucky will result in you losing money 99% of the time. The whole point of diversification is to spread out in to different assets which are not significantly correlated (or even inversely correlated) with each other, so if one tanks, your entire portfolio doesn't tank with it.
You don't diversify your portfolio by buying 20 different oil mining companies, or by buying 20 different precious metals. Similarly, you don't diversify your portfolio by buying 20 different random shitcoins. If you want to use bitcoin as an investment, then that's fine, but it should be part of a balanced portfolio of other non-crypto investments. If you want to take wild punts on random shitcoins, then consider that gambling and not part of any wise investment strategy.
This is why I do not trust any altcoin announcements claiming to be the next best thing they all depend on Bitcoin to some extent and they live and die by that sword. I just opened a topic asking participants of bounties that get paid in stakes and why they work for free with the promise of money in the future when the stakes are worthless. I cannot wait for some of the comments and I think a lot of them will be talking about not putting their eggs in one basket and diversifying their investments.....when they are not really doing that and are putting their eggs all in one basket. Cryptocurrency.