The second is that the performance is vastly improved. Why don't go go back up to question number one and read that second paragraph again. A common misconception. You can restore your files after they have been compressed with lzip. They just won't be exactly the same as they were before.
Compression is a dramatic process, and dramatic processes often change people.
It's no different for your files. On the reassuring side, it is important to note that the compression algorithm used by lzip only discards the unimportant data. In fact, many users may find that compressing their entire file system and then restoring it will be a good way to learn what is truly important. Simply put, a lossy compression algorithm is one in which not all of the data is preserved. The JPEG file format uses lossy compression.