Atm on my server where few people went for konan, after spending 20k they average 80-100 masked frags. So if all you care about is getting masked cheapest as possible, then this isnt event for you. However if you want to get a lot of goodies as well, stars are definitively an event to consider. Averaging those nubers, spending 5k on stars gets you enough stars to redeem 50 charms which already almost pays off the cost. In addition you get 20 masked frags (20x 120 from sage treasure price=2400), some scrolls and a chance for jackpot. Just keep in mind this is rng and those numbers are average.