ContribucionesMost RecentMost LikesSolutionsRe: What all is the usage adress used for? Usage address is just used for tax purposes.. E911 is a separate address. I've set my usage address to a state with low taxes with no issues. Re: Usage address doesn't match billing address Usage address is only used for tax purposes. E911 is used for 911, and can be separate. I've set my usage address to a state with low taxes with no issues.