Better balance, reduced canting error (admittedly a relatively minor thing except at very long range), and better height over bore (gets scope closer to actual trajectory, which makes for more predictable adjustment at extreme close and long range).
The big reason to me is balance. I don’t want the rifle to have a tendency to rotate around the barrel’s axis. Particularly with a heavy scope, this can be problematic if it is mounted too high.
Of course, if you have ever seen someone shoot the berm (or truck) because they forget that the reticle is 2-3” above the muzzle, then that’s another good reason.
Depending on stock design, it can also result in a better cheek weld. But this is highly variable. What works for a bloke with a big damned head or neck, might not work for someone else.
To me, the most important thing is that the scope and rifle naturally come to the right spot every time I raise it, without having to bend or raise my neck.