I’m not very informed about intercooler, but from the examples it seems to focus on AJAX requests. Stimulus is more about DOM manipulation, things you would’ve used jQuery for (except $.ajax and related). Toggle classes to show/hide things, move things around (mostly also just by toggling classes these days), create/duplicate elements, stuff like that. Stimulus also does some AJAX, but I can easily imagine these two work together in one page for different elements.
