Here's a good article on why the Pro will not replace your regular desktop (or laptop):
http://www.digitaltrends.com/apple/...-mark-in-its-attempt-to-replace-your-desktop/
This article unfortunately is attacking a bit of a straw man. It is attacking an idea slightly different from what people are actually planning, just different enough that it misses what these people are doing. And it's showing that people's computing experiences are starting to get diverse enough that some people simply
cannot fully get what other people are using computers for, and how they get things done.
Take my case. At work, a MBP isn't terribly interesting because it isn't powerful enough to get real work done. I see people try using VNC and the like, and it does the trick in a pinch, but it just isn't a long term solution. And if we are using VNC, you don't need a MBP to do that, really. So what I'm left with is a desire for an ultraportable that I can use during meetings and the like for notes, reference, task management and email. Something I already do on iOS today.
At home, our iMac is in the living room, accessible. If I need power, I have that right there. In fact, I do use it for photo editing and the like (been paying for Lightroom and PS CC, but I'm actually thinking of ditching it for Affinity Photo and just managing my library manually). Long term storage is on a NAS I can access from iOS as well as the desktop. But with both a nice tablet, and an iMac within easy reach, there really isn't much point in having the laptop there either.
When I'm on the road, I don't
want to do heavy lifting. Because I'm either on vacation, or I'm there to work with people. But what I do want is an ultraportable that I can use for reference, notes, communication, task management, and entertainment in my off hours. Split view and the larger screen make the Pro an interesting tablet for that use case. Especially once I can split screen a couple specific apps I'm still waiting on.
EDIT: I'll add though that if folks like Adobe want to make more powerful versions of PS and Lightroom available so I can do more on the road, I'll not say no. I actually hope that Affinity Photo makes it to iOS like they've said in their long term plans. But these for me are currently nice-to-haves, and not critical things. I can wait to get to my iMac to do heavy image editing, etc. About the only use case I *need* a laptop for is some forms of Astrophotography, since the software to control certain bits of hardware relies on Mac/Windows drivers, and can't be done over BT/WiFi yet. (Although I might be able to make a Raspberry Pi do the work... interesting...)