You’re not following the point of contention. An all-volunteer army versus an involuntary draft. The points you are raising don’t point to benefits of an involuntary draft over a volunteer army. America needed one of the largest armies in the universe to protect almost the entire continent of Europe and the entire free world against the threat of a nuclear armed superpower. It needed humongous amounts of armed manpower to accomplish that.
And it did so with an all-volunteer army.