Sounds like a semantics trick. Value is value. Sure, something can have a different value if you exchange it versus if you use it. It can also have a different value if you eat it, or drink it, or smash it, or wear it, or gift it to a family member, or gift it to a friend, or gift it to a lover. "Exchange" is simply one way of use.
Unfortunately, the labor theory of value is self-contradictory. If you invent a new machine that replaces human labor, it will clearly produce more value, yet human labour is reduced. So this follows that not all value can be attributed to human labor.
What this really breaks down is meritocracy. If you cannot unambiguously attribute "effort" of each individual (her labor) to produced "value", then such attribution cannot be used as a moral guidance anymore.
So this breaks the right-wing idea that the different incomes are somehow deserved. But this is not new, it's just more pronounced with AI, because the last bastion of meritocracy, human intelligence ("I make more because I'm smarter"), is now falling.
Addendum: Although accounts differ on this, Marx seemed to struggle with LTV, IIRC Steve Keen's Debunking Economics shows Marx contradicting himself on it.
Also in Marx theories exchange-value is something different than use-value, the latter being unaffected by automation.
Maybe Marx resolved the tension by converting the contradiction into a (wider) capitalism contradiction, and was happy with that solution. Whether it makes OP happy in the age of AI ("everything is capital and you're screwed if you don't own it"), not sure.