Yes and no. It doesn't care about what number you roll, just the result of the roll (success or failure). It will help you if you roll a 5 ten times in a row and you fail all those checks, but if you pass all those checks because of bonuses or because the target number was low, then it will make you more likely to fail. Although, in not actually sure you can get ten successes or failures in a row with karmic dice on.

In DnD your skill checks (except for opposed rolls c which we'll ignore for now) have a DC which is the number you have to roll to pass, that target number is shown on the screen in bg3. You also get bonuses to the roll (also shown on screen under the die). Attacks and spells with saving throws work the same way. Roll a d20, add bonuses, and see if your number was high enough to pass. Saving throws are slightly different because the defender is rolling, but it's the same idea, they want to roll higher than the DC of the spell.

So all that to say, karmic dice does NOT smooth the rolls and make it likely to get an even distribution of high and low rolls, it smooths successes and failures so that regardless of how hard a skill check was or how easy it was to hit an enemy, you will be more/less likely to succeed or fail m multiple times in a row.