To be honest, I think something like Smart::Comments is downright dangerous. I have run into the anti-pattern of comments that do more than just sit there, and I have never ends well. While I understand these comments can just sit there. However, the idea of embedding programming logic in comments is something which brings back bad memories.
More specifically it is way too easy to mistake a smart comment for a regular one or accidently write one. And it complicates reading comments. Good code is well documented with POD and sparsely commented but the comments themselves are an important part of the discourse about the code. One reads them and gets insight for why the programmer made this choice or that. One might explain why an unexpected structure exists, or why a given value is hardcoded. Adding a programming language to a subset of comments cannot help but interfere with that process. So comments as discussion about the code are valuable and this seems like it would dilute that value.
For those reasons I would never use that module. I think debugging logic is always cleaner even if the instrumentation poses some overhead.