1) putting pure cleanup code into different functions is unwieldy. It doesn't make code readability, thus maintainability, better in any way, so why use it?

2) speed. sometimes, when it comes to optimizing hot loops, there is a point where one needs to manually inline code, in order to avoid potentially unnecessary scope cleanups. Ever looked at assembler? Seen how many instructions a typical function call causes?

Of course, (1) is usually only relevant in systems programming and (2) is only relevant in HPC, where going that extra mile can actually save more than a few 100k$. Nothing the average programmer needs to worry about - however that's also one huge problem of that field: Lack of people with said know how.