The user interface of each is vastly different.
I have an amcrest 4 series, so I can't speak to the 5 series. But If I had one, I'd still be redundantly streaming the cams to Blue iris as well.
Blue iris is faster at search and playback, and my property that I manage is just close enough to the Bullshit, to have to review my cams every morning to see what crawled through the property.
I know within 5 minutes across 5 outdoor camera's whether or not I have an issue to deal with.
I cannot accomplish the same feat in my NVR UI. So while I like that it works, and it's recording, I find myself going to BI almost exclusively now.
You can have both.