Physics Material options are misleading? or misunderstanding?

So I recently started out with unity and decided to do the Brackeys guide.
In his you make a cube that simply move forward on a platform, in order to do that we make the platform a " slippery surface" using physics Material and setting both friction settings to 0.
now i would assume that setting both to 0 should actually work , but the cube kept slowly rotating on the y axis.
eventually I found out that "Friction Combine" : Average, actually doesn't average 2 zeros to zero, so when set to Minimum instead of Average the cube would stop rotating.
Now it's probably due to another variable that isn't visable, but I wonder am I the only one that is kinda confused here? can someone shed some light here ?

 

You probably want to check the two drag variables on the cubes rigidbody.