"Supposed to" is debatable. States do not have authority to tax interstate commerce. They go ahead and ask for it anyway. Although they call it a "use tax," the the tax is calculated solely based on the money that changes hands in an interstate commerce transaction. Looks like a duck, quacks like a duck, has webbed feet like a duck, as they say. It's an interstate commerce tax.
A personal expense does not become a business expense just because a taxpayer calls it that. But states think they can make an interstate commerce tax into a "use tax" just by calling it that.
A personal expense does not become a business expense just because a taxpayer calls it that. But states think they can make an interstate commerce tax into a "use tax" just by calling it that.