Interesting... I am a longtime Bootstrap user, and they offer a large number of other things that can be configured for the same purpose- alerts, popovers, modals, etc.

I've never actually noticed the toasts component itself, but have done the same thing with other components. I wonder if the feature was added after I started using bootstrap ~14 years ago, and I mostly just kept using the components I was used to.

Looking at it, I don't see myself using it because of the 'dismiss' button. I don't like things that obscure the UI, or encourage unneeded extra interaction, when I can pass info to the user without doing that.