AD-Blocking with unbound and pgl.yoyo.org/adservers

[Wayne Train]

Hi.
I included the yoyo ad-and-tracker-blocking hosts-file to unbound, but
I don't really understand why this zone maps to 0.0.0.0 instead of 127.0.0.1.
Can someone please clarify ?
Is there any special benefit of doing so?
Is 0.0.0.0 faster, or slower as 127.0.0.1 ?
Best regards,
Wayne