2/3 of the transactions are related to trading activities (I'm lazy to post a blog post about it, sorry) It means the majority is only interested in the cryptocurrency market to speculate, not because they need it IRL.
Lets assume the 2/3 is correct and the blog post wasn't some false blockchain analysis like they always are. And lets assume there were 9 million bitcoin users that means 3 million bitcoin users use bitcoin for payment and when the adoption grows to 18 million that means 6 million bitcoin users use it for payment.
The fact that number of speculators is also increasing is not going to change the fact that number of payments is also increasing.
(some sources say it is close to 100 million which would make it 33 million user who would pay using bitcoin).
It's the same with El Salvador, it doesn't matter if majority of people were only interested in that $30 airdrop. What matters is that many people who weren't using bitcoin (even if it's just 1%) before it became legal tender are now using bitcoin.