through Spirit Barrage with The Barber or Fan of Knives with Lord Greenstone's Fan). Certain builds can unleash devastating combos with a Power with proper preparation (e.g. Likewise, you want to use a Power Pylon or Shield Pylon at your moment of greatest strength, so it could be wise to find all the trash monsters around and bring it close before using it. Best case you can stack up 4 or more packs around a Conduit, have them already a little bit damaged and the trash cleaned up, and then activate the Pylon to finish them all. A Conduit Pylon should be used primarily for finishing off elites, as it's easier to mow down the trash yourself (benefitting from all the Area Damage you have). Make a pull around them, so you don't have to spend valuable time during their effect doing so. Pylons are precious and shouldn't be wasted, so especially in the big maps, you want to prepare for them. In the end it's not just about getting the right RNG, but also about using it to your advantage. Even at rather modest values of 5 or 10 stacked enemies, the effect is much higher than what other stats would offer: It's easy to see why AD generally outclasses these stats when pushing. Typically Area Damage competes with stats like Attack Speed or Average Damage (on Rings), both of which give you an increase of around 5-7% DPS per roll.
Here you can also see the value of Area Damage on your items: even at an extremely high AD value of 150% already present (almost every single slot you can have it, the absolute maximum is 198%), an AD-roll is very valuable with a 11.7% overall DPS increase (given you constantly attack 25 stacked targets at a time, which is unrealistic in solo gameplay but can be achieved temporarily with grouping abilities such as Piranhas Piranhado, Ground Stomp Wrenching Smash or Black Hole). This just becomes more as the values of AD increase, up to ~83% at 100% AD and ~88% of total damage at 150% AD. As you can see, even for a character using no Area Damage at all from their items (only 50% in Paragons), the overall damage done by it is still much higher than the base damage of the hit (over 70% of total damage done).