We have experimented with building an Android app in a hackathon last year.
This would work best if we implemented a Perl module. Calling Android APIs directly was a bit messy.
Another experiment was with an HBase table scan for some bigdata project.
These projects all used pre-compiled Perl to Java. Precompiled Perl can be potentially faster than "perl" - specially if you use typed variables.
The new thing in this release is that it can execute Perl directly, without precompilation - and it also executes BEGIN blocks and eval-string. Java applications can also "embed" Perl if there is a need for scripting.
Also maybe some company that is migrating to Java can keep using Perl, instead of rewriting.
tl;dr This is still new and I don't have a clear idea what it will be used for.