This is interesting, although I wouldn't be surprised if Github eventually (if people start using this) tried to stop people from doing it since it causes them to effectively lose money.

Also, unless the person running the workflows is doing some extreme penny pinching, I doubt this will see much use because it seems like it significantly increases the time to complete the various workflows while only saving a small amount. One extreme example being the 8.8x time increase running express's tests, from 59s to 8 min 42s