Why is segmentation good for the customer too?
An example: you have three readers, Tom, Dick and Harry. They all love to read. Tom is a big fan of Stephen King and would pay 30 euros for a Stephen King book. He also wants to read his newest book the second it is out of the press; every day after that is causing him anxiety.
Dick likes a good horror book, and Stephen King is a good horror writer. So Dick would pay up to 20 Euros for a Stephen King book.
Harry likes to read, but he can only afford a novel if it costs 10 euros or less. There are lots of Stephen King books he hasn't read yet, so he doesn't have to pick the newest.
If Stephen King's publisher does not segment, they could make the price 30 euro. They'd sell a copy to Tom and get 30 euro revenue. Or make it 10 euros, then they'll sell 3 copies á 10 euros, also 30 euros revenue. At 20 euros, they'd sell 2 copies, and have 40 euros revenue. So they sell it for 20. Tom is happy. Dick has a good book and is happy too. Harry buys no book.
With segmentation, the publisher makes a hardcover edition for 30 euro and a year later, they publish a paperback for 10 euro. At the beginning, Tom buys the hardcover and is happy. A year later, Dick and Harry both buy the paperback for 10 Euros.
Harry is definitely better off with segmentation, because now he gets to read the book. Dick is also better off, because he pays less. Tom pays more than in the non-segmentation case, but is still very happy, because he loves Stephen King. Besides, in a more realistic example, the price of the paperback is not set at the reservation price of the biggest fan, meaning that Tom gets 100 Euro worth of pleasure of his paperback and not 30, so he has good value for his money too. Besides, in a typical market, there are a lot more consumers like Dick than superfans like Tom, so collectively, the segmentation case is better for the consumers.
Of course, it is better for the company too, because it makes a bigger profit. But actually, if classic economic theory holds, it is a win-win situation for seller and customer.