@marnanel from what i understand, the soviet union also had a system where numbers were associated with letters to "ease memorization", but each digit only got one letter, starting with А and skipping Ё (because it's too similar to Е) and З (because it's too similar to 3), but eventually that system went away, because the soviet-era rotary phones i used (i was born after it dissolved, tbf) didn't have them and no phone numbers were spelled out even in old materials, and the next "let's associate digits with letters" idea instead happened with mobile phones when they had to figure out how to type text messages on a keypad