The reason was it let you get Nullification down to a VERY low CD. I could pop a nullification every 5-6 seconds if I needed to, and because the build is squishy, reflect targets a PoS, and such, it’s just very nice to have. For the most part, I had already maxed out everything that needed maxing, and a few more points in Maiven’s would have given me less overall survivability than the points in nullification gave me by far, in both being able to just nullify every single hero I came across without an issue, rather than having to save it for “High Threat” heros or reflect heros, increases it’s reduced elemental damage debuff (Which effectively increases my survivability against elemental damage, a nice bonus), and I just liked the feel of being able to nullify anything on demand rather than a few more points of absorbtion.
Seriously though, Nullification had saved me from my own high DoT damage several times, because each SS could very well chunk more than half my hp bar if I hit a reflect target. Being able to nullify the reflect from the target, AND the DoTs I had just hit myself with, at the same time, frequently, was a very big QoL improvement.
I had Maiven’s ranked up to a break-point, and more ranks past that would have had low yields per point unless I could get some serious overleveling on it, and I knew for a fact I couldn’t because of how much gear SS depends on to be maxed out perfectly at the time.