Yes @Amigo1989, you are correct, because the visit counter is based on visitor level the average visit is on higher side.
As per below snapshot for reference, It's 1 visitor and 1 visit for the given campaign, but if you consider creating segment at an visitor level then the average visit it will return as 11.
Now to answer question "how often users have a visit just for this campaign" then my approach will be Visits/Unique Visitors, 27842/25339, on an average only on 1 visit users visited this campaign.
If you would also like to view on which visits they viewed this campaign, then dimension visit number will be helpful to give details around whether they visited this campaign on their very first visit or on their return visit to the site.
Regards,
Godwin