Very interesting technology, field tested and with a committed userbase. An adjustable keyguard could easily become the next big accessory for mobile phones with larger screen (particularly foldables) - the portion with a tactile keyguard on would generally be used as a "keyboard" featuring application-specific buttons, but hopefully obviating the current need for "dead" padding and larger touch targets.
(OP) I think that would be a great idea. My friend is the person who wrote this article and he uses the ECO2 as his speech device. It can be SUPER cumbersome to bring it everywhere. It needs to be attached to his chair or have someone else carrying it, which kind of defeats the purpose of easily accessible communication.