None at all!
"...links clicked on within the Windows Mail app will open in Microsoft Edge..."
This will have as much impact as if email addresses clicked on within Microsoft Edge would open in the Windows Mail app. i.e. None at all!
MISTER PROSSER: Have you any idea how much damage that bulldozer would suffer if I just let it roll straight over you?
ARTHUR DENT: How much?
MISTER PROSSER: None at all!