It's true that they're experimental, but it's extremely unlikely they'll be removed. The only reason they weren't stable in the most recent version of perl is because of some interactions with subroutine attributes (specifically, :lvalue) which needed some tweaking. We use them everywhere at Fastmail and they're great.

Which is to say: a lot of the reason they're still experimental is because Perl's commitment to backward compatibility. Other languages might have said "oh well," but Perl 5 said "oh, an unintended consequence that might break real uses in the wild; we should wait another year."