User blog comment:AssaultTrooper/About SAS/@comment-27003001-20170608143552

End game prem weapons are like either weaker or better than endgame non-champ weapons that has a unique special ability. Also, most of them need cores to eliminate their great disadvantages. Some late game prem weapons still get their jobs well done on lvl 400 matches.

NK didn't make them competitive for VS like some late level non-champ weapons and as strong as champ weapons for balance, so you won't see a top players on champ using prems. I myself is a prem-user player.  These are the only late-game prems: