Explain how this is good for the consumer?
-If a consumer is the type of person that doesn't care about PC's, but does care a lot about performance, this can be good for them, since they now have an option to upgrade.
-If a consumer hasn't bought a PS4 yet, and wants to get a fancier version of one to make use of their new 4K TV or whatever, it's good for them. As with pretty much every other console that's been release throughout history (and technology product in general), if you're willing to wait a bit, you can get a better deal. It's up to every individual consumer to decide how much they want to wait.
For others who already have a PS4, and aren't the type to be super concerned with graphics (assuming a basic minimum playable standard is reached), it doesn't really do anything for them. Which is fine, as obviously not every product fits every consumer's needs perfectly. But it doesn't hurt them either since they're still getting all the same PS4 games, and support isn't being cut off for it. They've been able to play all the current PS4 games, and they will continue to be able to play future PS4 games.
At worst, some developers might ignore the base PS4 version and pour all their optimization time into the Neo version, leading to a worse experience for the base PS4 owner. But that happens already (other platforms exist, after all), and has happened throughout the entirety of gaming history, so it's not like the Neo would be the cause of this problem. And of course, there's no market incentive for developers to do that, so they would be hurting themselves. So the chances of it becoming a pervasive thing seem pretty low.
The only way it becomes a pervasive thing is if somehow the Neo comes out and completely outsells the base PS4, and everyone starts to get rid of their old PS4's. But that scenario likely wouldn't happen until years from now, at which point it would be new console time anyway.
edit: based on the above post, I suppose the person more likely to be "hurt" is the person who bought a PS4 just before it was announced. Which does suck. But as with the "developers might make shitty PS4 games now!", that's hardly a PS4 or Neo specific issue, unless we're arguing against
any hardware change at all (so I hope the folks making that argument also aren't the same people that are salivating for "Slim" revisions)