My read is that the spell does an amount of damage that is still less than that of disintegrate even if the full measure is dealt.
At the same time, it
* consumes your concentration
* will only cause minimal damage if your foe is one of the 11% of monsters immune to charm
* will only cause minimal damage if your concentration is broken
* will basically never CC the target unless there's no combat happening OR the target would die to the spell
* still lets the target act while avoiding the damage
I took a random flick through some high power threats, and there's a lot of things that are going to either just take 5d10 and ignore the rest of the spell because they have truesight or are uncharmable. Then there's a lot of things that are going to just sit in it and keep hitting you because they can see through it and have functional ranged attacks.
Personally I think it ends up in a niche where it's just not a good enough damage spell to be a damage spell, and it's not a good CC spell at all.