Lots of people in Latin America prefer to work with dollars when they can. Look at what the government of Argentina has been up to recently in terms of limiting the population's access to US dollars if you don't believe this.

People in high-inflation places can benefit from holding dollars instead of their local currency - and one easy way to get ahold of them is just to accept them as payment for goods or services.

Agreed, I was just in Costa Rica and most businesses I encountered accepted USD. I also think its ease of conversion with the local currency helped as no calculating was really necessary.

You may be thinking myopically if you are just thinking of mom, and pop fish n chips store. Because, how do western European oil companies.. buy oil(which can only be bought and sold in US dollars)? How do western European electronic companies get parts from Taiwan, and Japan without outrageous exchange fees. Do you think these companies switch back and forth from euros to us dollars.. or do you think western European companies(especially manufacturing) just keep, and use US dollars. The entire world economy depends on the US currency platform.

Just because it's illegal. Doesn't mean it's not accepted.

So a currency isn't a platform by which we store, and exchange value. Interesting.