Dialogs are a great way to lose information. They are often dismissed by users that want to do their job and are interrupted by modals. Users focused on their tasks blindly dismiss dialogs.

Read the above as a critique to your strong opinion and not an opinion of mine.

My opinion is that toasts are great for notifications that can be reviewed/checked later, like chat notifications or finished background tasks.

What should be avoided, just for the same reason as modals/dialogs, is an overuse, causing fatigue.