Yup, its for automatic simplicity and lightness. You can get -- if everything is adjusted right -- the same bearing surface with much less lug. So, theoretically not as huge a barrel trunnion, etc.
In practice, this seems to never pan out really. It would seem some middle ground, like some triangular "three lug" systems I recall seeing might be it. The AR's 22.5° system seems to have its following though, so its mostly that or garand/ak style two lugs over what, 60°?
For bolt rifles, I can hardly see how the overall design really matters. Even things totally shocking to us today, like the rear lugged Enfield, worked just fine for decade upon decade. Quality of build and fit seems more critical than any specific system.
In a related vein, I have always thought it would be cool to have a straight-pull-type of camming action where the firer lifts the bolt handle thru something trivial like 15° but the bolt head rotates more like 60°. Presumably rotation and unlocking could continue thru some lateral movement, to alleviate primary extraction issues...