I’ve done a lot of web development and never heard the term. I even use them a lot but called them popup notifications or other terms. I’ve used lots of frontend toolkits that call these something else.
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.