I don't know how good cursed chests actually are. Hellrift for instance has a very high chance for cursed chest and is a very short/easy run, but since the bounty XP was nerfed on it, making that the smaller part of it, you barely get over 1b/hr with it even though it's constantly doing cursed chests. Hellrift and Old Ruins are the only two cursed chests I know of that are always in the same spot(s), the Old Ruins one being a guarenteed spawn if the bounty is there, and Hellrift being probably 2/3, all while still being very short and easy runs. Old Ruins seems to average out at spawning like 2-4 an hour which is basically never, so you'd end up with just a Hellrift profile, which as stated isn't very impressive.
The fastest way I have found to level honestly is Greater Rifts. The old best method was doing the highest torment rift that you could still complete in around 10 minutes, now that T6 is piss easy you want to do the same thing with grifts and just keep running them. I do 35-40s and average about 3-4b xp/hr, by hand though because even as good as the rift profiles are, none of them can run a rift as smooth as a person, there will always be an issue of backtracking. Not to mention it seems like Trinity isn't fully there yet with supporting my Monk, stuff that is unbelievably easy by hand the bot will continuously die on.
Just for reference for anyone curious about my claim, I can run a T6 rift in under 5 minutes. Running a modified SWK Monk with almost perfect gear.
Kind of sounds like bragging reading it back, but what I mean; If you want XP run the highest grift you can that you can finish in around 10 minutes, it is the best XP you can possibly earn right now, it's why all the streamers do it literally all day. Even Gabynator the highest paragon player when playing in non-season runs grifts to XP farm, and if anyone knows anything about farming XP it's him lol.