Quantity is the most important thing.
This is why LK is a single player thing. You can spam this and only this on a 2x bonfire map that'll never change. So in 1h if you're fast you'll have opened up LOTS of chests with a good chance of an HR in each. The important part is "lots" here.
It's the same for Pindle, it's a single player thing because you can hard spam him with 2 guaranteed items every 15s or so and 2/ You can MF up disregarding your DPS because you'll only do Pindle.
On BNet because of game creation restriction, it is much more worth to do Pit/CS/Baalruns and only that to make the shortest games possible while killing the most ennemies possible (you can even drop The Pit depending on the number of player in the same IP and your clear speed). In the span of 5-10 minutes you'll have killed LOTS of alvl85 ennemies, and in the span of multiples hours, having a few more CS runs is way more powerful than opening ~100 LK chests.
That's why most ppl report that they find pretty much all of their HRs in CS, myself included.