I've always seen buying altcoins and stocks of cryto companies like exchanges and mining farms as adding another layer onto your bitcoin investment. By doing so you're really buying bitcoin, just with another multiplier on top of it that will lose value if the underlying asset (bitcoin) loses value, but can also lose value by itself, for instance if someone happens to the person behind it.
Let's say you have Coinbase or Microstrategy stock and the CEO gets abducted, or arrested, or is killed in an accident, the stock will plummet. Why would you need that layer of risk on top of your bitcoin?
What if bitcoin crashes? These stocks will also crash, so you don't have any immunity from bitcoin dumps, like you would have if you owned real estate or gold.