In this case bigger AOE mean that it can stun vehicles in quite a big area and that it can wipe out support teams and garrisoned units quite good...
And that is why I said that comparing gammon with satchel is not really helpful in the first place...they both do a big boom and the similarities end there...
The hammer gammon is entirely dodgeable. it's got a 12 meter throw range with a 3.3 seconds fuse. The Molotov have 15 range and the two allied grenades have 20 meter range.
Any units should really be moving or watching out for explosives if an enemy unit get that close. Tanks shouldn't really be loitering that close to infantry units to begin with. Too many take the tommies' lack of regular tank snare for granted.