Yeah, I mean... seaxes are cutting weapons. I think one of the big re-enactorisms of the Gwynne books is treating seaxes like important weapons of war, which tends to come from re-enactors kind of piecing together their own version of history from the archaeology that they don't necessarily understand. Lots of people seemed to carry a seax with their weapons, therefore seax = weapon.
The reality seems to be that the seax was just a utility knife that basically everyone carried, and it just so happens that people carried their utility knives during war as well. I mean, you can use it to fight with, and certainly many did. But it -started out- as just a common tool.
That's why the seax is single-edged with a flat back. So you can press your hand down on the back of it while cutting things like meat or rope or whatever. Also, the complete lack of guard means it would be very dangerous to thrust with, especially against hard targets like armor/shields/bone. Good way to slice your hand wide open AND lose your last ditch weapon.
I can't speak to the quality of the one you got. I don't know if it's basically a knife-shaped lump of metal or made to exacting specifications of historical originals. But my experience with seaxes designed after originals is that they tend to feel like clunky kitchen knives. They're okay, but they don't necessarily index -great- or move particularly gracefully. But again, they are primarily cutting tools, not weapons of war, as far as we can really tell.
Fun fact is that the seax design was basically the standard European knife carried by all classes, including knights, until quillon daggers became more popular in the late 11th century. So this 'Viking' knife was carried by Christian Crusaders into Jerusalem on the 1st Crusade.
