That's the same speed already offered in a few states so it makes sense to bring it to everybody. Lower price plans are expected to see increases to 20Mbps and 10Mbps from 15 and 5 respectively.
So if they're increasing speeds what's with the talk of using copper for some future expansion? Basically it's a question of economics. So far Verizon has been able to stick with fiber because they're sticking to urban and suburban areas.
The problem comes when they decide to move into more rural areas. Running fiber gets much more expensive a the amount of cable per customer increases, which is exactly what they face in rural areas. It's the same reason rural areas tend to have fewer options for internet service now.
While it would be nice to see Verizon stick with fiber for every customer without exception, if they can deliver something faster, cheaper, and more reliable in areas where choices are limited right now it still has to be an improvement.