verified boot seems like the only advantage here. You can buy an ebay business-grade laptop with TPM for 40 bucks USD readily, and they don't require reliance on Google or the requirement that one uses a neutered OS. (yes, yes, it's secure. It's a users' platform. Development on chrome OS at this point is an act of masochism.)
If secure travel is your thing, stash your data on a cloud provider and pull it later after you arrive at your destination. Go whole-hog and travel without an SSD and buy a cheap one at your destination with cash. Sprinkle in some libreboot for more confidence.
It'll still be cheaper than a 200 dollar chromebook, and you probably won't have to deal with some of the worlds' worst chicklet keyboards.
P.S. don't travel with a yubikey that isn't partnered with another. Would be a bummer to lose.