I suspect we find the Vikings so interesting because they played an outsized role in the development of modern England, from which most of us still derive our basic historical template. Point of view counts for a lot in writing history.
And then later due to their harrying Harold (he defeated them) his army was too tired to fend off William
By themselves I am at a loss to understand what roles they directly played.
As in, for instance, this?
"...they were certainly violent, but so was everyone else at the time -- and still are."
I.e.:
"We must understand that by today's standard the Vikings were normal, I mean one just has to look at high school shootings, everyone has an automatic weapon when all they need is a bucket of rocks, etc."