Digital copies of anything will have their quality greatly reduced. Look at digital cameras for example. They take the pictures but need to cut out a lot of the detail that nature presents us with, replacing them with separate pixels of individual colour. It's impossible to be as detailed as real life when you're copying a brain, and so that form of "living" isn't immortality at all. Even if it was possible to be immortal, it wouldn't matter for 99% of the population as most people won't be able to afford this immortality, and we'll just be using even more resources to feed the immortals, which will lead to an ultimate end of human life on earth as we run out of resources. This is happening anyway, but immortality will just make it faster.