Labour theory of value puts value on goods for the sole purpose of trading and explaining trades. Both LTV and STV does.
Marx’s use of LVT is to criticize how Capitalism leads to exploitation. But although the specifics differ SVT could still be used to raise the same critiques.
Probably because unlike paying for the service, we don’t feel how it takes our money from us.
A psychological trick that works so great that it made a lot of services exist in the first place like the whole of YouTube. And now we’re kinda addicted to those too.