Thank you for your comments. Each of them has a point.
I see the TextBlade keyboard as an interesting innovation which enhances the use of mobile text entry, which can be categorized like this, for example:

(A) "2-thumb text entry on glass": virtual keyboard on touch screen. No desktop needed. Medium speed, looking at the key labels is essential. Quite prone to errors (hitting an adjacent key, no or poor "click and feel"). Examples: the virtual "2-thumb" keyboards of most smartphones and some tablets,

(B) "2-thumb text entry on physical keyboard". No desktop needed. Medium speed, looking at the key labels is essential., Less prone to errors than (A), thanks to 3D shape and tactile "click" of the keys. Examples: the virtual keyboards of most smartphones and tablets, Examples: TOHKBD for Jolla phone, Nokia N900, Nokia E7,

(C) "Physical QWERTY for 10-finger touch-typing". Mainly on desktop. Speed of typing: high, if the writing person has an acceptable touch-typing skill. There are only minor layout differences between the mobile, laptop and desktop Qwerty-keyboard variants. In most situations, you don'nt need to look at key labels. Less prone to errors than (A): eight fingers have their "home keys", each letter is entered with a standard finger movement, good tactile "click and feel". Examples: TextBlade, mechanical keyboard accessories for smartphones, full-size Qwerty keyoards of desktop and laptop computers.

(D) Other, "Non-Qwerty" keyboards, such as text entry on 12-key numeric keypad of phones, and chording keyboards. They require special skills: on them the touch-typing skill on stardard Qwerty keyboard cannot be reused.

Please note that here the "stardard Qwerty keyboards" comprise also their language or country specific layout variants, such as the Cyrillic, Greek, French (Azerty) and German (Qwertz) layout.

In the C.category, I see TextBlade as a promising innovation, if its claimed good features come true also in practice. It does not need to replace B-category keyboards, such as TOHKBD for Jolla. But it has potential to generate new product concepts. For example, if attached to an "Other Half" or a "back plate" of a smartphone or tablet, the TextBlade keyboard could work as an essential component of new kind of ultraminiature computers, which can replace the conventional Qwerty keyboards of laptops and some tablets (those of Microsoft Surface, etc).

Personally, I would like to see the TextBlade keyboard fixed to the "othert half" of a Jolla tablet or phone.