Here's an example: you buy some embedded hardware for a personal project, but you find out that the toolchain for that chipset is a pile of proprietary blobs built on Clang and it only runs on Windows. If it were built on GCC, then the GPL would force them to make the source available and people could adapt/update/rebuild it as needed.
Making something MIT/public domain is free for one hop, from you to the next person. After that it can become even more restrictive and demanding than the GPL (i.e. proprietary binaries).