It makes a big difference, because compression and TV settings are very much different things. Compression aims for perceptual transparency: which data can be

It makes a big difference, because compression and TV settings are very much different things. Compression aims for perceptual transparency: which data can be removed from the signal while not changing a human's experience of that signal? That goal is typically not achievable with the available bitrates in video codecs, so instead they aim as close to this target as possible: remove as many bits as you can without seriously reducing quality. Your argument that 1% is "a tiny amount of data" is technically correct, but missing the point entirely. A vast majority of the perceived information in the signal is retained. This is even more true of sound encoding, where true perceptual transparency can be achieved on most samples at startlingly low bitrates. TV settings, on the other hand, can alter the perception of a signal a great deal because that is what they are designed to do. A good TV (and good settings) and a BluRay will get you much closer to the original signal than an average TV and an uncompressed master.