It has a lot to do with the C/Unix culture of computing. Generally, there's a rule that writing functions longer than a screenfull that have more than ~7 variab

It has a lot to do with the C/Unix culture of computing. Generally, there's a rule that writing functions longer than a screenfull that have more than ~7 variables is frowned upon - the rationale being that we humans are not too good at tracking more than 7 things at a time. When you stick to these rules, short names for variables become a no-brainer and arguably make code easier to read.