I guess writing for class has always been about the process and not the result. Nobody has ever wanted to read an essay written by a student. But, the process of writing the essay is useful; collect sources, read them, distill down the important points, join the points with sentences. ChatGPT is all about the end result. Assignments are about the process.
If they can't do basic arithmetic, there's no way they can understand the actual concepts underlying math, or have any type of number sense (and they don't; though, granted, neither do most of their elementary school teachers). It'll be absolutely horrible if they have no idea of how to craft a coherent argument, or deeply think because ChatGPT just spews out something (and who knows if it even gives factual answers; they'll never know to check). Couple this with other issues arising from over reliance and overuse of smart phones and we're setting ourselves, and them, up for a grim future facing serious existential problems (.i. climate change)
I see so many kids who don't know that, for, say, 28 + 35 you can simply rearrange this to be 30+33. They have no concept of what addition means, or how you can regroup parts. Same with breaking down multiplication and how you can do it by parts and then sum it. They have no concept of how the numbers work, basically, and I don't think algorithms would give them that sense, it'd just give them steps to compute stuff.
To some extent, you are probably thankful your elementary school teachers didn't let you use a calculator to do stuff like 2 + 2 = 4 or the multiplication tables. Doing that quickly without any tools is useful in the real world.
Similarly, you will often have to argue for your point of view in real-time; there won't be time to craft a prompt and ask the AI what it thinks. "Why should we do this your way?" "Why should we hire you?" "Why should I let you go with just a warning?" It all matters.
All of this is just various levels of abstraction. It’s still your responsibility to manage the final outcome, which is a far distance from “assembling words.”
It can be useful to know how to use a tool, and can also useful to know how to do similar things without that tool.