It also has something to do with atmosphere. A cafe should have light chatter and people socializing. If the majority is sitting around in silence, it takes away from the special feeling a cafe normally has. I could get coffee at home for a fraction of the price.
If people start using Cafes differently, why hold them to a forgotten standard? Cafes should see a business opportunity in that they can align themselves further with the needs of the consumer. Either that, or the consumer walks.
Open, unrestricted wifi comes to mind as an example.
Also it's somewhat off-putting for the people trying to have the leisure.