1. It is difficult to losslessly compress something that has already been losslessly compressed, because its entropy/bit will be very high.

2. De-compressing something you already had losslessly encoded feels like learning or discovery, depending on whether it is externally induced.

Like, if you know the statement of a difficult math problem, then you know enough information to pin down the answer, but you do not know the answer. If I tell you the answer, you will feel like you just learned something. And you did, in some senses of the word, learn something.