Different people have way different uses for these things, I've seen people willing to pay way more than the asking price for a Surface Pro.
When I'm on an overseas trip I use these things everyday, sometimes hours per day, booking hotels, flights, cars and restaurants and looking up places of interest.
I edit large photos, 16 megapixel and collate hours of text and photos, some of this stuff I would call very serious work. But I would be able to do even more on a Surface Pro.
With the Surface Pro I would have a USB slot and an SD slot and use thousands of programmes.