There are only paperbacks. By "hardcopy", they meant "printed".

I sell print editions through Amazon KDP and IngramSpark. Amazon is the lion's share, so I designed the print edition based on the formats they offer. At the time I started working on it, KDP only supported soft covers. They added hard covers right as I was finishing the book, and I didn't want to have to go back and redo everything.

I have to admit that "Crafting Interpreters" is pushing the limits for what you can get away with on a soft cover. When I first started writing the book, I expected it to be (much) shorter, but I just estimated wrong.

If I had a time machine, I might go back and tell myself to print it as two separate volumes.