No Thanks a Mint

Imagine that you're on a trip, and you stay at a hotel. At the end of the day, you wash up, done brushing your teeth and all that, ready for bed. You walk over to it, and ... there's a chocolate sitting on your pillow.

What exactly were they thinking when they came up with that? Why would I want a chocolate (or a mint) as I'm about to sleep? Who's the clever one who came up with that idea?

The only origin I can think of is maybe some twisted play on "sweet dreams".