Oh are we back to "Bitcoin is unstable" FUD. I missed the memo. I was still going with the "Bitcoin is bad for environment" FUD. I also loved the "blockchain good but Bitcoin bad" FUD while it lasted, that one was fun.
The US is El Salvador's largest trading partner - so Bitcoin's price relative to the USD does matter.
100% on bitcoin means no services, no goods, an economy where nothing but bitcoin exists. As soon as I need to drink water the price of water and the income of the operator of the well will go down over time because of the fixed supply and the hoarding of currency.
If you wanted to add more things to your list, try "the majority of people buy it because they hope someone else will buy it for more in the future."