Technically speaking, if "time spent" is the factor you're looking at; People do usually spend time working. Every $50 someone pay, they (or their significant other or parents) worked for.

If you meant spending time ingame; Sure thing. I can understand, respect & agree to that.
However, FC probably noticed a lot of people not interested in PvM (thus offer tokens) and a lot of people not interested in PvP (thus offering VP). Just a theory. Also, please notice how the tokens are significantly cheaper in $ per effort than the VP. Might have something to do with what you can get with each of them.