To me, the imply that there's a hypothetical event log that I could view if I needed to look back to see what happened. In reality, that event log doesn't exist in an accessible way, and it's true that once the toast message times out, it's gone forever.
The log is just an optional added feature. The main point is for the current/last message not to disappear by itself, and to be displayed in a non-distracting and non-obstructive way.
