I think a ChromeBook with really first class support for Linux apps is very compelling. I run Linux in a VM on Windows 10 on my ThinkPad and it's a great setup. A ChromeBook would be a very similar setup but probably with better native OS integration (for example they are exposing the Linux filesystem in ChromeOS's file browser) and this would all be a first class use case supported by Google.
Macbooks continue to look less and less appealing to me, if Chromebooks somehow got Adobe CC, I'd switch immediately.
Most of the time, I'm either at home or at work, so I just remote log into my development systems. I, personally, don't really need to lug around my entire development environment, though I used to be in that school of thought.
So, given that I really just need SSH, a decent Chromebook is cheap (as others mentioned), and can have a decent keyboard with long battery life. The one I have is around 1kg, so it is very "handy", and I carry it everywhere, as I would have a notepad in earlier days.
It can also make sense if you like physical function keys and/or a touch screen larger than a function key row. :)
I used a Chromebook Pixel with Crouton very happily for a year. Granted I spend 95% of my time in Emacs and a web browser.
1. The security model is fantastic compared to the alternatives. DIY security is an endless distraction these days unless it's your full-time job. I am concerned that the team may not be able to keep things so secure as the complexity of Chrome OS increases, but as a starting point it's still the most secure commercial OS out there.
2. Little to no setup. Boot it up, log in, and you're ready. (And now, I guess, install whatever Linux apps you want.) This makes it easy to recover from hardware failure, even if you're on the road. Just go take one off the shelf, no worries about installation, configuration, etc.
3. Disposability. Most Chromebooks are incredibly cheap. If it breaks or if you lose it, it's not the end of the world.
4. Easy, safe sharing. If someone needs to borrow a computer to check their email, you can log out and hand it to them. Your stuff is securely encrypted, and the system is hardened against compromise. This may not be a big deal for everyone, but it brings me great peace of mind!
The promise of Ubuntu Convergence and Windows Continuum on a single piece of hardware, solving the "app gap" with Android support - the best of the web, Android and one's choice of Linux desktop.
An ultrabook/iPad substitute - "power users" requiring a 32GB Core i7 desktop replacement might look elsewhere, naturally.
The hardware support has been really nice, as a lot of the usual linux fiddling required to support monitors, etcetera has been much easier with the intermediate chromeOS layer.
This is not my primary machine however. I only use it at home to ssh into my desktop once in a while.
They seem to be going for the same price range.
Besides this was an impulse purchase. I was tired of my home laptop and wanted something so I went to best buy and purchased it within half an hour. I can't say the same for x230.