because it shows adoption and its value compared to USD. In reality the USD value of bitcoin shows the collapse of the value of the dollar as much as it does the increase in value of bitcoin.Then why do you keep comparing its worth to the dollar? Without the dollar, Bitcoin has zero worth, even though I'd argue it is still worthless except for the fact we have so many greater fools on this planet. When the dollar goes to zero, Bitcoin goes to zero.
Look at how Russia just had its money stolen from it becuase it was USD. Do you really not see value to other countries being able to hold a money that cant be stolen from them if they piss off the world police?