Generally, cryptocurrency portfolio diversification reduces the risk But comes out with a lower return compared to the opposite strategy.
Diversifying is a good idea, but doing it in unsystematic way is such a YOLO idea. That's when it becomes very risky.
How does diversifying in other cryptocurrencies reduce the risk compared to just being invested in Bitcoin? As already said by other members in this thread altcoins rely on Bitcoin and if Bitcoin goes on a bull run so do the altcoins. What do you mean by unsystematic way? That makes no sense if we have already established that altcons rely on Bitcoin to an extent.