Not only are nicknames easier to read, but they're actually more anonymous than initials. If you're A and your partner is P and your other partner is S, then someone who knows all three of you might be able to put it together. Nicknames, on the other hand, can bear absolutely no relation to the real person. Indeed, you can make them deliberately obscure just to mislead people. For example, Cue has absolutely no interest in pool.
“As I am sure any cat owner will be able to tell you,
someone else putting you in a box is entirely different
from getting into a box yourself.” —bisexualbaker