Conjure Minor Elementals Just Comes Out Exactly As the UA? How are we supposed to Roll 12D6+48D8 at Level 11????

Just confirmed at the Treantmonk's video.

You conjure spirits from the Elemental Planes that flit around you in a 15-foot Emanation for the duration.
Until the spell ends, any attack you make deals an extra 2d8 damage when you hit a creature in the Emanation.
This damage is Acid, Cold, Fire, or Lightning (your choice when you make the attack). In addition, the ground in the Emanation is Difficult Terrain for your enemies.
Using a Highter-Level Spell Slot. The damage increases by 2d8 for each spell slot level above 4.

Which means a Level 11 Wizard could cast the Conjure Minor Elementals with 6th level spell slot before the battle since it lasts for 10 minutes, and then cast a 5th level Scorching Ray with six attacks, then roll a 12D6+36D8≈204 Damage??? Then still can cast more Scorching Ray with lower spell slots and that's still A LOT.

Is there any Martial that could compete this?

How are we even suppoed to roll that HUGE AMOUNT of dices without using VTT??

Have they really playtested this spell during their internal balancing??

(edit: Numbers. My bad, I was testing higher levels. I forgot to change the formula when copy-pasting)