Transfer size is one thing, but the JS code has to be parsed and executed on every web page load. Moreover, it is often loaded as a blocking <script> in <head>. My point is CSS and no JS is better than JS.
If you don't use JS at all, you don't pay the price too and it's faster since there is no JS to parse and execute - see e.g. https://github.com/niutech/phooos
https://bundlephobia.com/package/htmx.org@1.9.11