In the documentation for both Tooltips and Popovers is the caveat: "opt-in for performance reasons, so you must initialize them yourself." But I'm having trouble finding a detailed explanation of "performance reasons." The caveat is at least 6 years old, which makes me wonder if it's still true.

Also, many people miss this caveat when reading the documentation, for example #24985 and #15458. So it would be great if Tooltips and Popovers could actually be automatically initialized in a performant way. That might also pair nicely with using MutationObserver to automatically remove Tooltips in v5.