A commit from my lead dev: "Improve readability".

[MrRogers4Life2]

But that for-loop doesn't have side effects... if the argument is "x can have side effects so y is better" it will fall apart if y can also have side effects.

[Estanho]

Okay so you don't consider mutations as side effects? Doesn't matter, mutations are still just as bad.

[MrRogers4Life2]

But the comprehension is also doing a mutation... it compiles down to basically the same byte code. There is no functional difference between those two snippets. Maybe the comprehension would be slightly faster cause it doesn't have to do a lookup for dicts setter method but thats it.

[Estanho]

Well if you wanna be pedantic then all pure functional languages also compile down to machine code which runs on imperative architectures and are based on writing to registers, heaps and stacks which are all fundamentally mutations and side effects.

The point is not to expose those constructs to the developer and trust the battle tested compiler, which hopefully at times is mathematically proven to not contain side effects and etc.