yes, it clearly does not matter in this kata

Context is important. In this context, only one variable was necessary. If two variables were necessary it'd make sense to leave them as two separate variables, and in that context I am sure most would make the appropriate decision that provides the best solution to optimize their performance, completeness, and simplicity of their codebase

while it clearly does not matter in this kata, the "why not" may come into play where one should consider whether the a and b in the original setup are potentially required somewhere else in the code landscape. eliminating them may turn out to be disasterous. this is pure supposition, but perhaps worth consideration

I decided to golf this one too because of you. I managed to get mine down to 190 characters.

I know. I really wanted it down to 256. :)