Except I've seen countless times that users ignore stuff if they can, including important warnings etc. Ideally confirmations should be kept to a minimum anyway (and instead ensure all actions are reversible), but in cases that's not possible I'd rather have a confirmation show in a modal where I can at least see the page/context it's referring to (and it goes without saying, all modals should be draggable, even for touchscreen devices) than a separate page entirely. And if an action can't be performed then I'd much rather see the reason why in a modal window that grabs my attention and forces me to acknowledge it than a button that appears to do nothing but cause some easy-to-miss message show up elsewhere on the page.