Got one ... of those levels, but I didn't like the level being so low. I like the scope mounted levels because I can be "in the scope" and still glance at the level with my left eye. I often do too.
I agree ... "practical difference" being the key. Short range probably doesn't make much difference if you're close to level. Still, it doesn't take but a nanosecond and it doesn't hurt. I was very successfully shooting my little AR15 out to 900 yards and I swear much of the success was religiously leveling the rifle with a quality level as part of my shot sequence. It's become a bit imprinted for me now. I just use inexpensive levels on my crossbows.I really don’t pay that much attention to it. Just an occasional check to see how I’m aiming without it.
The X1 is so consistently accurate without it I don’t see how it will make a practical difference.