Your baseline reveals more than your occasional peak.

Anyone can produce something excellent once, given favourable conditions and enough time. What your baseline shows is what you produce under normal conditions, which is most of the time, and that is a far better indication of what you can be relied on for. Peaks are about potential, baselines are about reality.

Judge yourself and others by typical output rather than best output. It is a less flattering measure and a considerably more accurate one. It also points you at the improvement that would actually change things.