that is slightly incorrect,
to clarfiy:
its still a buff even with the attribute on.
meaning its: +50% offensive property effects with buff on while reduce 50% of strong property penalty.
e.g
if you use a fire skill on an earth monster you will do 50% more damage.
if you use a fire skill on an earth monster with EE on you will do 100% more damage instead.
if you use a fire skill on an earth monster with EE + attribute on you will do 75% more damage instead.
in comparsion:
if you use a fire skill on a fire monster you will do 50% less damage
if you use fire skill on fire monster with EE + attribute you will only do 25% less damage instead.
its a very interesting skill. if you happen to be a tao against lightning bosses this skill alone will enable you to do much more damage with your burst combo while in general scenarios its still good for all-round usage.
it would be better if its buffed though, like increase the duration to at least 1 min instead of just 20 sec dura.
if you hotkey the attribute then skilled usage of this ability will bring many benefits.