Yes it will cause a lag if you set the area to global if there are huge outnumbered units in your map because they're all having buff effects
no effects btwNope, it wouldn't unless you have insanely high particle buff effect for the aura then yes it would lag. But with the normal aura? I don't think it would cause any lag. Test it and find out.
Lags will occur if you have greater than 600 ally in the map and if the buff is highly particle. but it will not cause a lag if the buff is just normal like the buff of Brilliance aura or devotion aura.
EDIT:
@Hell_Master
Why lag?? I tested it in the map with brilliance aura global.
Since even in DotA ( the global aura of Crystal Maiden ( Brilliance Aura ) )
Lags will occur if you have greater than 600 ally in the map and if the buff is highly particle. but it will not cause a lag if the buff is just normal like the buff of Brilliance aura or devotion aura.
EDIT:
@Hell_Master
Why lag?? I tested it in the map with brilliance aura global.
Since even in DotA ( the global aura of Crystal Maiden ( Brilliance Aura ) )