I believe the description was updated in the meantime:

... return it with its digits in descending order.

Comments are things to be ignored when compiling
For example you would not preserve comments in C to the byte code
So likely, this line could be simply dropped when parsing

I'm not understanding how to handle comments exactly

Namely: rem &&Some comment~!@#$":<

This line has characters reserved to BrainFucks' operators. How do we transpile these comments to BrainFuck?

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

whats cheatin about it

lol the kata did say it was supposed to store "codewa.rs"

Three years and a couple thousand solutions further, it hasn't been fixed. I guess it's not going to be fixed.

Closin.

client might not care but the next developer after you would. lol.

cheater

What????

Personally, I favor performance over readability because clients/users/customers do not notice nor value elegance as they do speed

While it may be faster, its a little more difficult to read and understand what you're doing. There's more to best practices than faster code.

I believe that without self it would not know what iterable object it was iterating over.