The kind of person who is using Block's bitkey is using multi-sig & presumably trusts block - they don't feel the same need or requirements for a screen as someone who might be using a more personal device like seedsigner, where the user is in full control.

As people start abstracting control away from the individual they'll stop looking like electronics we're used to and more like trinkets you interact with tangentially (like the bitkey where you only touch a pad)