GT can't guarantee +4, but it can guarantee a +2 at least once. Lets say we get red coin (in this case red coin is worse.. weird I know). Opponent plays Longship and you play Saber. Opponent plays An Craite Raiders on melee. Lets say you move the ship to ranged with GT and play (for the sake of it) Cat Witcher. Now, the opponent plays any card in any row and because of GT's one charge, Saber gets +2 at least. Without the GT's charge in the beginning, on red coin, the Saber would have played for a wholesome of 7 for 9 the entire round. With GT's charge, it at least gets +2.
I know it is very inefficient to use a leader charge in R1, but at least it gets +2 (and indirectly another +2 or something since, most likely the opponent will abandon one row). Saber and GT will put the opponent in a tight spot even though they are not getting more points. Another interesting theory is, as your second card (after you move Ship to range), you play Dunka. Now the opponent wants to kill it. If he uses Stunning Blow, both the units in both the rows will get damaged. So, would he play a unit to save the damage or will kill Dunka? (He can play Vabjorn for a stunning blow, but it loses him the opportunity to play it Champion's Charge or even Blood Eagle later).
#justTheoryPlaying