Toasts (those little pop-up notifications) are bad UX because they always appear far away from where you're actually looking and interacting on the screen.

So when you click a button in one spot, you get a confirmation message somewhere completely different that you might miss entirely.

It's much better to show feedback right where the action happened - like changing the button text, showing a loading spinner in place, or having something visually change nearby so you immediately know your action worked without having to hunt around the screen for a tiny notification that will disappear in a few seconds.