In my experience, if you're going to aggressively componentize whatever you're building (i.e. a button isn't a css class on a simple `a` tag but a distinct component that exists in it's own file somewhere) there's huge advantages to having your styling be associated directly with your components, and Tailwind is a great option (among many) for that.
If you're building something where your unit of organization looks more like a "page" than super fine grained elements, Tailwind will just make things messy and a higher-level library or writing your own CSS would be a better approach.
I don't think this changes much with AI - right now most models are not terrific at maintaining a huge degree of context in larger projects, so I could absolutely see an agent implementing CSS that works well in isolation but breaks due to the cascade. Maybe that changes in the future, but right now if anything I think Tailwind is well suited to AI because it enforces a certain locality to the changes you're making (i.e. you can reasonably assume that a `text-red-500` class on an element isn't going to break things elsewhere and wll do what it says on the box).