You miss the point. Using the style attribute everywhere causes duplication; using css classes can quickly lead to bloat where you have lots of unused classes.
This is a way of paying only for what you actually use.
Assuming the content is gzipped when transferred (a good assumption), the non-Tailwind version's payload is smaller because there are no separate CSS definitions.
Your statement is true in the general sense (a page can easily load unused CSS with other CSS/styling approaches) but I don't think it's correct to say that using Tailwind results in smaller payloads vs. using style attributes.
Someone should make a compiler that converts inline styles to Tailwind so then you don't have to learn Tailwind but can still use Tailwind.
For example it can convert `<div style="background-color: white">` to `<div class="bg-white">`. Perfect! (Yes, "bg-white" is the Tailwind way to make the background color white.)
Yet again, inline css has no support for media-queries, pseudo elements, states(hover, visited, active). Tailwind does. Tailwind also works as a design system, limiting you to a predefined font-sizes, spacing, etc. generating a consistent look-and-feel that requires discipline to do with inline styles.
This is a way of paying only for what you actually use.