bioseq is a command-line program just like lwp-request. In the distribution tarball it is located in the bin directory.

The name suggested, Bio::BPWrapper:bioseq, is wrong. That may be where metacpan may find it, but that is not the name. It doesn't have a package namespace of Bio::BPwrapper.

As for why I did that, it is because I want the POD which is long to be separate from the code so that the same file can be put on a shared wiki, but combined with the distribution just before release.