Comment by rz2k

They are like Vim. “Alt,letter,letter,arrow,letter,letter,arrow,enter”, etc. Rather than a single combination of keys, it is a series of key presses.

I agree that it might be trivial to set up for spreadsheets, and it would be really useful for other spreadsheets, and many other applications. I suppose a hurdle is how context sensitive the commands are depending on the cell or range of cells activated, and their contents and data type.