On my website I have a sidebar (on large enough displays) where I put sidenotes (which I typically prefer to footnotes). https://chrismorgan.info/blog/dark-theme-implementation/ is an example of an article with both float-based sidenotes and grid-based figure captions in that sidebar. Look at what happens on mobile-sized displays, too. https://chrismorgan.info/blog/2019-website/ is an example of where float really shines on this, with the second sidenote automatically moving down the page due to the length of the first sidenote.