I'm getting PHP notices with the plugin activated, and I've noticed several threads where users have reported them and you've said that they're harmless.
I agree that they're not indications of fatal errors, but I don't think that means they should be ignored. One of the most practical reasons is that they can screw up the theme layout, especially if XDebug is installed and outputting the call stack.
They can also cause pages to break by outputting headers prematurely, and by outputting notices in the middle of HTML tags.
Here's a good thread where several leading devs in the community argue that notices are errors and should be handled.