The ATECC608A is a very nice feature. I have an older version of the USB Armory--i.MX53 and USB-A. The cryptographic engine (SCCv2), and in particular the AES module with unique, secret eFUSE'd key (for creating a proper HSM) was poorly documented. NXP only made security component documentation available under NDA, and to achieve that you needed to work with a reseller, which after repeated attempts over many weeks I never managed to accomplish. Plus, even if I got the documentation, the keyed AES module only worked properly if you had secure boot working, otherwise it used a fixed test key rather than an alternative unique key. This was such a steep hill to climb that none of the example or open source applications ever made proper use of the AES module, AFAIK.

I ended up simply buying a Pi 3, a Mikroe Click shield, and Mikroe ATECC608A board (for the shield), though by that time I had already run out of steam so I never had a chance to bring it up.

So, the ATECC608A is very nice and I'd like to see it more widely included in hardware.[1] And the armory is much smaller than my literal Pi 3 hardware stack. Bonus points if documentation for i.MX6ULZ and related bits are publicly available, but I'm not keen on risking another goose chase so I probably wouldn't even factor that in one way or another.

[1] I believe an ATECC chip is what AWS originally used for end-to-end hardware attestation of EC2 servers. And maybe still do. Though, this is speculation on my part based on some AWS developer blog posts discussing the chip.