[Strilanc]

A government site has implicit authority. You could use that implicit authority to make a scam look more authentic. It also will have a lot of traffic; a lot of opportunities for the scam to work if you do manage to get in the middle.

For example, inject a dialog box that says "Our records indicate your taxes were not paid this year! Before you can view the weather you must click here and log in to resolve this issue!".