Can confirm: even if the precise implementation changes, the array will always be forced into a contiguous form before being turned into a pointer; if it's being done so immutably, this may require a copy that gets thrown away.
(There is a scenario in which this is a performance concern, the same way as it can be for Strings! But it's a lot less likely to come up in practice. Still, maybe we'll want contiguity detection for Array at some point too.)