wgetpaste needs xclip for some features, as pasting form X copy buffer or copying output into X copy buffer. Reproducible: Always
Created attachment 230215 [details, diff] Full ebuild patch
Wgetpaste functions just fine without xclip, so it isn't a needed dependency. At best it would offer optional extra functionality. But as this doesn't change anything in the installed files of wgetpaste itself, there is no need for a useflag. Note that adding/changing a useflag would trigger a reinstall which is completely unnecessary in this case. The best here would be to follow the normal policy to add a post-install einfo message.
