The internet only says that because of the double-banishment build (which I believe they're now the only book that can still do it). War Altar, level 4 light (power stone), two level 1s on light (dispel scroll and forbidden rod), celestial hurricanum. That gives you a beastly banishment battery, with 2d6 S6 on the level 4 and 2d6 S7 on the altar, and enough power dice generation to run it.
But unless you're taking all of those pieces, light is just a reasonably useful buff lore. You can help your guys hit or not get hit, maybe shut down a magic phase with net, or clear some chaff with the magic missiles...but that's about it. It's still your boys doing all the heavy lifting, and if you messed up your play on the board there's nothing in Light that's going to bail you out (no dwellers, no purple sun, no pit of shades or mindrazor).
If you're looking for a crutch lore then Life or Shadow both go very well with Empire. But honestly I think Heavens is the better lore if you're looking for something robust enough to compliment your play rather than dictate it. Harmonic Convergence protects your knights from rubberlancing or rolling the dreaded '1' on armour saves. Iceshard Blizzard helps you break foes in combat (and is probably one of the best sigs in the game). Curse of the Midnight Wind protects you from poison and killing blow, and makes you harder to hurt. And the ranged spells offer you a very strong, flexible toolkit. Comet is perfect for breaking up castles or crippling an opponent's back lines. Chain Lightning can do the same, and is even better against fliers. Heck...even the hex spells become pretty solid for dealing with fliers (cheap d6 S4 is nothing to shake a stick at).
The ranges are a lot better than light as well. 12" is reeeeeeally short when you get right down to it. I've run light with my Tomb Kings and it's frustrating how easy it is to venture outside that bubble, and when you've got some 800 points invested in squishy wizards you don't want to get super aggressive with them either.