From what I remember, being able to pass children as a prop is considered a side-effect of an implementation detail, that breaks the expected abstraction. There really isn't any reason to use it, and I think there's a chance it may even limit what the virtual dom diffing can manage?
Also this would prevent you from accidentally doing both at once:
<MyComponent children={<div>Is it me?</div>}>
<div>Or is it me?</div>
</MyComponent>
(I don't remember what React does in this situation)
I use it fairly extensively whenever I have code like <Cpt>{props.children}</Cpt> (i.e. whenever the only thing I'm doing with the children prop is passing it to another component. This comes up pretty often with context providers, where I'll write a provider wrapper that handles some stuff by itself, and then passes the value and children to a React context.
I like using the "children" prop explicitly because it's a lot more concise (with prettier, I can often go from five lines to one line with this style), and because it's more explicit. I'm not creating my own children, I'm not adding anything to the markup myself, I'm just passing the input children directly to another component.
This isn't really anything unusual, it's exactly what JSX compiles to under the hood. And passing JSX elements in props rather than as children is useful in other contexts as well - for example, a button that allows <Btn icon={<MyIcon />} ...>
You're right that this can cause odd situations where children are specified in two ways, but I'd rather have a lint rule explicitly handle this case than disallow using the "children" prop altogether. (In fact, I think Typescript does validate this case already? But I might be wrong there.)
I can see why this rule might be useful to have in general, but I agree with the previous poster that it's a semi-opinionated rule, and one of the sort of rules where I end up having to disable it and fiddle around with configs whenever it comes up, which in turn puts me off using ESLint in general because I know to get it to be useful I'm going to need to spend some time changing everything up.
From what I remember, being able to pass children as a prop is considered a side-effect of an implementation detail, that breaks the expected abstraction. There really isn't any reason to use it, and I think there's a chance it may even limit what the virtual dom diffing can manage?
Also this would prevent you from accidentally doing both at once:
(I don't remember what React does in this situation)