Is it worth bothering to use a module to slurp files (in Perl5)?

That's for you to decide, but IMO, in general, no. I feel that adding another dependency for the convenience of saving two lines of code is not a good idea, especially if you intend to distribute the code. However, I'd feel free to use it for internal project if I found it convenient enough (which I don't) or if I needed better performance and found that this module provided it.