what is the difference between crit dmg and crit chance?

Critical Strike Chance is the likelihood a basic attack will deal critical damage.

Critical Damage is the amount of damage a critical strike will deal.

Critical chance is the chance you will crit. So if you have 30% crit chance then you will crit 30% of the time.

Critical damage makes your crits hit harder.

Crits are extra damage

One works as a RNG multiplier to overall DPS, where as the other works as a multiplier to the RNG multiplier...

Wait, if we can achieve the same effect of crit by simply increasing auto attack damage by a set %, why do we still have crit?... RIOT!

.... this guy is pulling your legs, it's literally in the name