Historical requirements. When computers first began to be used for Syllabics, the most important thing was to be able to input, display, and print the needed characters. Since it was earlier much more difficult to alter some aspects of the user interface than it is today, solutions for placement of Syllabics characters were based on the English-language Latin-script keyboard drivers implemented in the operating systems. In order to place the final syllable series on the unshifted numbers (where they are very convenient for users), it was necessary to move the numbers from their existing positions in the code table to other positions.
This, while expedient for input, is a disaster in terms of functionality and text interchange.