I've used chromebooks as my primary laptops for dev stuff for ~7 years now. No regrets, but there are tradeoffs that are worth considering.
Things in my situation that I think make this work well are:
I have a "real" machine in a desktop (or a work laptop, if that's what an employer gives me), I don't consider any laptop my primary personal machine in any case. I'm happy running what I want in a linux CLI-only environment. (You _can_ do gui, but you start pushing the hardware limits of the lower end machines pretty hard.) I want a light, cheap, reasonably secure, and ultimately disposable machine that I'm not concerned about tossing around, throwing in my backpack, leaving out on a coffee shop table while i use the restroom, etc...
Issues I've hit:
Poor/no docker support. I've just remoted back to home for things that need it and that works, but isn't ideal if you want to work disconnected. Occasional linux apps that require an X server -- either don't offer a CLI or do something stupid where even the CLI tries to connect to X. Internal storage tends to be limited and non-upgradable, SD cards are the portable option, but slow, and lugging around an external HD is a pain.
(Also, I haven't actually played with the new crostini stuff at all yet. I'm still on an older machine with crouton.)