IMO it is a net negative.
10 years ago redditors took some pride in transparency, you were able to check who you were talking to based on their profile (unlike boards like 4chan). Now it's auto-generated user names with hidden everything. Might as well get rid of unique names and profiles at all and call everyone anon.
Agreed. Hiding history has become a negative signal or, really since it's so common to hide, open history is a positive signal.
There used to be bots that summarized an account's posts. One, I think it was usersimulator, was particularly amusing as it ran a markov chain over the account and generated a fresh post in the style of that user. Quite telling.
I still use reddit but I tag accounts using RES and sometimes see the same bad apples turn up in other subreddits.