It's worth noting that for highly-compressible types of files, if you do need to use base64 for some reason it's still more space-efficient to compress first (before base64). If you can compress to 2/3 the size, base64 will only bring it back to the original size again.

This mainly applies when you have to transmit binary data using a text-based format like JSON or XML. I've also used this before to build a shell-script-based installer, where a compressed archive is base64'd in a variable.