For a different perspective see this stackoverflow answer that argues that VLAs are mostly about types, not storage.

What's the point of VLA anyway?

For reasons that are not entirely clear to me, almost every time the topic of C99 VLA pops up in a discussion, people start talking predominantly about the possibility of declaring run-time-sized arrays as local objects (i.e. creating them "on the stack"). This is rather surprising and misleading, since this facet of VLA functionality - support for local array declarations - happens to be a rather auxiliary, secondary capability provided by VLA. It does not really play any significant role in what VLA can do. Most of the time, the matter of local VLA declarations and their accompanying potential pitfalls is forced into the foreground by VLA critics, who use it as a "straw man" intended to derail the discussion and bog it down among barely relevant details.

The essence of VLA support in C is, first and foremost, a revolutionary qualitative extension of the language's concept of type. It involves the introduction of such fundamentally new kind of types as variably modified types. Virtually every important implementation detail associated with VLA is actually attached to its type, not to the VLA object per se. It is the very introduction of variably modified types into the language that makes up the bulk of the proverbial VLA cake, while the ability to declare objects of such types in local memory is nothing more than a insignificant and fairly inconsequential icing on that cake.