There is no reason to leave Infernal Hordes this season except for bossing reasons and I’m not sure this event is great enough to justify that.
It varies based on what spires you get in your run but on an average T7 Hordes run I am spending about 15 minutes (vendoring and all included) and getting between 500-700 aether per run.
If you spam the materials chest you get so many stygian stones (which sell for 20-30m each) that you would never want to click the gold chest or go to pit for stones. Even if you do click the gold chest you get at least 2x more gold than you would farming whispers. You get enough angelbreath that there is no reason to ever go to helltide. You get twice as much neathiron (roughly 600 every 15min which is a full 8/12 → 12/12) for time investment as you would in the pit. You can farm all of these things simultaneously and most optimally in 1 room.
On the other hand clicking the greater chest and the equipment chest will give you like 2-4x more GA items than any other content ever could. The GA chest alone gives you more GA’s than the average content, let alone if you use the equipment chest also.
Thus the only reason to ever leave infernal hordes is to farm boss mats and do tormented bosses, and even then it’s now so easy to get all the mythic uniques that the only reason to do more than 50 or so total tormented runs (8-10 rotas, unless you’re really unlucky) is if you want to farm greater affix mythic uniques, which is somewhat sadistic.
I feel like getting this many rewards from one content should be tied to the pit (in contrast with d3 grifts) since that is the most rewarding and replayable part of the game that pushes your character the most (whenever leaderboard gets added and pylons get improved etc).