Hello! By default (it is also impossible to disable this) seahorse build plugins for nautilus and gedit. By make it possible to disable these it will limit needed dependencies, thus make it possible to use it on non-gnome desktops (or non-nautilus) like xfce. To bug-wranglers: Please, let the maintainer decide here.
Created attachment 93468 [details] seahorse-0.8.1.ebuild Proposed ebuild with added USE="gnome" flag that decide on further gnome integration (and building of gedit and nautilus plugins). This is based on totem resolution to disable additional, unneeded gnome features.
changing to gnome as this is the stable branch
Done in 0.8.2 (in unstable).