Picky Reviewer HELP 💠

I've been away for a bit from the app, but can someone help me understand: why do some campaigns say "Picky Reviewers" & others don't? Does that mean I won't have as good of a chance to be selected since I'm not part of the Picky Squad? If I apply to one that says "Picky Reviewer" what does that mean exactly? Thanks in advance ♥️