Is Devel::PreProcessor used when compiling Perl to bytecode?

Nope, it's just source-code manipulation; it produces a single file that contains the source of your script and the modules it uses.

...the following was among the limitations listed for Devel::PreProcessor: ... use strict and no strict pragmas are removed ...

Assuming your code already compiles under use strict, there's not much of an impact if you then remove that pragma.

However, in hindsight the solution to this wasn't very difficult to implement, so I've made this change and released a new version of Devel::PreProcessor to CPAN; it should show up on your local mirror within a day or so.