DSC gives a few advantages over traditional imperative scripts:
– Idempotent resources. We're expected to write resources in such a way that they can be executed over and over again, and will leave the system in exactly the state it's supposed to be. I don't know about you, but I didn't always put quite that level of rigor into my older scripts. 🙂
– Monitored for drift over time. Depending on how you've configured the LCM, it will keep an eye on the things you've told it to configure, and either log an event when something's changed, or it'll just correct the problem.
– Declarative syntax. Easier for non-developers to write and maintain, if that workflow is appropriate for your organization.
That said, if you want this to be a one-time file copy, there's really no reason to bother with DSC. (And in fact, you'd be overwriting any other DSC configuration that was already present on the target systems, if you used it for such a small task.)