You may have to wait a while if you want a Mac with an E Ink keyboard. Wall Street Journal tipsters understand that Apple wants to make Sonder's e-paper keys a "standard feature" on MacBooks, but that it's aiming for a 2018 launch. Don't expect to see anything at that reported October 27th event, then. At least we're getting a hint of the functionality. As you'd expect, E Ink would let your Mac use "any" alphabet, along with special characters and media editing shortcuts. You could write emoji more like you do on a smartphone (where you replace the keyboard with an emoji picker) instead of using a keyboard shortcut and wading through an on-screen dialog box.
None of the companies involved are commenting. However, Sonder had already acknowledged that talks had taken place. The technology would make sense, however. So long as Apple is still philosophically opposed to touchscreens on its computers, any input innovation will have to take place below the display. See those rumors of OLED touch strips on the next-generation MacBook Pro, for example. This isn't going to make you happy if you prefer touch, but it might satisfy creative pros, emoji fans and anyone who has had to go without localized keyboards.