It isn't just about blocking those that haven't uploaded avatars. Egg users stick out because they have other properties such as

New account follows a lot quickly, but doesn't have followers

New account that with time never ever tweets, only retweets and follows

New account that starts and then immediately follows just a single person ever.

All of those are suspicious

>New account follows a lot quickly, but doesn't have followers

>New account that with time never ever tweets, only retweets and follows

Both of these are also the behavior of people who use Twitter simply as a content stream. They pretty accurately describe how I use Twitter.

So no one will see the tweets you already aren't tweeting?

Given the penalty is limited reach, sounds like there'd be no effect on your use case.

Some do upload