Why would someone buy a scope like this? It's essentially a spotting scope mounted to rings.
Yes. You answered your own question. Having essentially a spotting scope mounted to rings is a *good thing* for ease on the eyes, PROVIDED that weight/size is not an issue. Higher Resolution. Low light transmission during legal shooting hours (yet low light) back in the woods under the canopy. Lack of blackout. It's unnecessary, but easier/fun to use. But you're right; for that kind of dough, I'd get a Gen 1 or Gen 2 night scope, or an Elcan Specter DR instead.
And it's a Diavari, not Divari - their mistake, not yours. I do fail to understand why a 34mm tube and this scope are "ideal for magnum rifles". The larger objective with heavier glass actually means more momentum under recoil and thus more stress on the body/tube - more prone to damage/failure. It's actually more ideal for a medium- or light-recoiling range gun
ATN makes an 80mm scope - ridiculously overpriced. I have a 60mm scope on a .243 - it's for fun - it helps newbies too - newbs have a difficult time with eye alignment & blackout - this helps to make their first scoped rifle experience positive.