Well Guardsmen are going up in points, but even anti-tank to make then -1 BS (1/2 wounds to a tank) against 3 tanks is better than killing 2 tanks a lot of the times, especially if you already have a -1 to hit.
Auto-hit tanks are different, but LRBC for an example, when hitting on 5+ and 6+ they dont really have much of a threat.
Making them move is important too, another reason you need terrain, without terrain then just take 9 LR's, etc.. if you dont need to move and can see everything then its just a free for all at who can shoot better.
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