Better energy transfer, less wear, smoother and quieter. 
transfers the load forces on the gearshaft away from perpendicular.
If you’ve ever driven a Lada Niva with square cut gears you’d understand why helical gearing is so much better. 
Try an International Scout. Straight cut gears! Was a running joke with a friend of mine that’s sadly passed away these days. We had some fun that’s for sure.
Lada Niva, those rust buckets don’t even go do they
Look forward to a review
Not anymore.
My mate bought one in the 90s… absolute Russian POS.
Weirdly though, they won best compact 4x4 in 2021. 
I know but then you can’t get parts for them. Plasiba