I think I'd better describe it as helping in the case of identifying information being correlated over time. Even if you've got good OpSec, you may reveal thin

I think I'd better describe it as helping in the case of identifying information being correlated over time. Even if you've got good OpSec, you may reveal things about yourself accidentally over time, and with a long-lived nickname, this could potentially narrow down your identity. Things like colloquialisms/references that are culturally specific/indicative, or reference to things that indicate things about yourself by association. This could potentially be counteracted by analysing usage patterns/language patterns to try and associate a set of nicknames as 'the same person', but it's probably hard-ish to do if communication is terse + sparse.