how does CONCENTRATE works? and how useful is it?

I alrdy have the active skills i need for my build and I have more than 20 SP to spare, im thinking of getting this skill but i dont know how it really works and if it is worth it.

 

- Concentrate: unlocks Spellburst ability, this is the equivalent of a "critical hit" but with magic, the chance will be extremely low though, just like the Smash battle skill. Only useful to invest SP on Concentrate if you are a glass cannon type of dps mage (no focuses elsewhere other than damage).
Result of maxed Concentrate: I.e. Out of 100 Impacts 1-2 will hit around 150% higher.

 

Thank you so much for this. That's only around 1%-2% chance.....

 

i heard crit stats will add to it