If service to others and to society mean anything to you, working in Starbucks or any fast food job will teach you more about humanity and human society than most college grads learn from a humanities degree.
It's not about learning "more". It's that earning a degree is an academic undertaking whereas working at a coffee shop is "real life".
There is no need to treat one as more or less valuable/useful than the other. They're just different kinds of human experiences. Learning is possible from both.
If you meant doing a service job at a small business, where you can have real ownership over how it treats its customers, I would agree with you.