The Xfce devs likely decided to reuse existing packages from GNOME – Xfce is also based on GTK+.
You can set GNOME or KDE services to launch at startup: xfce:xfce4-session:preferences [Xfce Docs]
About gnome-keyring, Xfce does not provide a keyring manager, so you may need the one from GNOME or KDE for applications that require it.
Thanks folks,
IMHO it seems like a naive way to mix DE since they market xfce as being light but at the same time seems to be relying on gnome stuff a lot (e.g. missing crucial stuff like keyring manager) which btw I wasn’t aware.
The total installed size for all 3 packages mentioned in OP is 19.5MB, so I don’t think these packages require Xfce to reconsider any claim to be a lighter DE