But wherein does that meaning lie? If the two strings represent the same text, you can't tell the difference between them, because there is none.

(I guess technically you can't tell the difference between an ASCII string and a string of random 8-bit numbers in the range 0 <= x <= 127, but if when represented as ASCII characters those numbers are meaningful -- comprehensible English, for example -- the odds are good it's the former not the latter.)