In reply to:

I have been told that the main reason why $2 bills and 50-cent coins are rarely seen in the U.S., although plenty were issued, is because there is no slot in the drawer of a cash register for them...

Funny, I've always heard that it was due to the tendency for collectors/packrats to hoard them.
My guilt is not only implied, it's admitted.

And jmh, I'm with you. Bills are smelly.