Taking off with a tail wind is a little more involved than that it increases the chance your wing will dip on your turn out causing a slide
When you take off into the wind the wind will catch under your wing the underside of the wing is not your lifting surface
When you take off with the wind the wind will catch on top the wing this creats turbulance on your lifting surfaces.
Yes its true that most us will not have to worry about these things but if we are going to fly scale models of an airplane we should at least know what and why a full size reacts the way it does.
Scale is not only how it looks but how it looks in the air.