I'm not sure if you intentionally missed my point. Everything in C requires careful usage. VLAs aren't special: they're just yet another feature which must be used carefully, if used at all.
Personally, I don't use them, but I don't find "they're unsafe" to be a convincing reason for why they shouldn't be included in the already-unsafe language. Saying they're unnecessary might be a better reason.
VLAs are unsafe in the worst kind of way as it is not possible to query when it is safe to use them. alloca() at least in theory can return null stack overflow, but there is no such provision with VLA.
Who out there has a version of stack checking that doesn't actually check the stack…? If it doesn't check by default, as C doesn't, then it's not "as long as".
Too bad we have all that legacy C code that won't just reappear by itself on a safer language.
That means there are a lot of not careful enough developers (AKA, human ones) that will write a lot of C just because they need some change here or there.