This is a great question! After playing it some, I think that Locket definitely has its space, particularly against bursty compositions, but I would generally dissuade Karmas in low elo from building Locket. Item actives have their own learning curve, and I FIRMLY believe that low elo brackets should focus on fundamentals without worrying about actives. IMO items that trigger automatically are probably better.

However, I should also say that I'm on the Radiant Virtue (Sad) Hype Train. All Aboard?