As someone who recently purchased a Vortex Spitfire 1x Prism Scope, I can easily say that now is the time to buy one since they're on sale.
The etched reticle means that even if the batteries run out, the optic is still usable. As for co-witness, out of the box, a Gen 1 Spitfire sits at a height which provides a 1/3 co-witness, and I'm not sure that it would even work out at that due to how blurry the front sight appears through the scope.
Fortunately, you don't really need iron sights with a prism scope, so it's kind of redundant/superfluous to co-witness with one anyway.