The appeal of bitcoin to me, a regular American, is much the same appeal that using a VPN, having encrypted hard drives, and not sharing information about myself all over social media does. There is very little ability to have privacy when paying with USD. You can have cash transactions, in real life, or send money orders through the mail. That's pretty much it.
I want privacy in my spending and in my assets. If I like reading about hacking and buy an eBook about it, I don't want that to be evidence against me when law enforcement comes knocking and tries to trump up charges against (see HN post about this just today). If I buy a VPN service, I don't want to become a target for surveillance. There are tons of legitimate, legal reasons to want privacy in purchasing and assets.
Publishing your entire transaction history for the entire world to see doesn't seem like the best way to have privacy, even if it is under a pseudonym. After all, purchasing history seems like one of the best tools to trace a pseudonym.
We can have as many pseudonyms as we need, and can transfer Bitcoins among them via mixing services. No pseudonym need make more than one purchase. It's the difficulty of anonymous postal delivery that's limiting.
You can do the same thing with USD. It's called money laundering, and was not invented by the Bitcoin community. Granted, for the time being it's a lot easier to do with Bitcoin, but any kind of mass market adoption would surely change this.
All of the things mirmir mentioned are considered money laundering when done with USD, so they either solve that problem for both or for neither. Neither result is an argument in favor of bitcoin, so whether or not they do is immaterial.
Postal delivery of physical goods is problematic, and anonymous payment is pointless. But that's not an issue for software licenses, ebooks, server and VPS rental, VPN subscriptions, consulting services, and so on.
I want privacy in my spending and in my assets. If I like reading about hacking and buy an eBook about it, I don't want that to be evidence against me when law enforcement comes knocking and tries to trump up charges against (see HN post about this just today). If I buy a VPN service, I don't want to become a target for surveillance. There are tons of legitimate, legal reasons to want privacy in purchasing and assets.