More evidence that these pop-up bubbles are not helpful — even for the purpose of training new users:
In the thread linked above, the user did not know the purpose of the gear icon in the URI field, and therefore did not even notice that the icon was there. Thus, they had no reason to hover their mouse pointer over the gear, an action that is wrongly assumed to always be performed by users who are confused about the interface.
A more effective use of a pop-up in the above context (my preference would be the standard rectangular tooltip, not the new bubbles) would be for the tip to display the current setting for the URI match detection. Just displaying “Show match detection https://www.example.com/” is not very informative, whereas the following pop-up text might at least have some value to a user:
“Change match detection (Base domain)”