Unfortunately, this misconception or perhaps misguided idea of the value you get when paying for work is still surprisingly common today.
Yes, for lack of a more accurate measure work is generally measured in "hours spent". However, as an employer or as a client, what you actually want is not someone's wasted hours but the business value created during those hours.
Insisting on someone filling an office chair just because you paid him to do so seems petty. It's almost this liege lord kind of thinking comically displayed in Dilbert where the people you pay to play "butts in seats" are your part-time serfs to do with as you please.
