They look like good products, but my daughter had a really bad experience with them - she bought one, it arrived with the screen broken, and they refused to accept that was possible and said she must have broken it and refused a refund.
Unfortunately Onyx Boox have used sockpuppets and other dirty tricks on Reddit[0] and elsewhere to harass and deter users reporting broken screens. Their international partners have webpages explaining how it's "impossible" that e-ink screens can be damaged or broken without you dropping or sitting on them[1] And in general the company is hostile to anyone with damaged devices or issues of other sorts.
Although no-one is perfect, I really like Supernote and their way of developing as much as possible in the open[2]. The devices are really great to use[3]
Throwing another vote out there for Supernote. Very responsive, particularly around handwriting - which feels flawless. Been a perfect device for me, but more limited than a Boox. That’s fine for my use-case, but still worth calling out.
If you're using a credit card for its benefits (like buyer protection, which I have several times over the years) and have the money to pay it off immediately, it's not pointless debt, but a net benefit to the purchaser.