The Greek word used here, μάχαιρα, while technically referring to a type of ancient Greek single-edged sword made of bronze, here presumably refers to a sword which would be much more typical in the first century.
A gladius-type sword had a blade that was commonly under two feet in length, was two-edged and made of iron. Iron, though strong and able to keep its edge better than bronze (which was in use in earlier periods), can be quite brittle, and the longer the blade, the more breakable.
The comparative shortness of the gladius (or of other ancient swords, for that matter) should not be thought of as a deficiency. The martial arts of the day suited a sword like the gladius, which was used for thrusting and cutting, rather than for fencing. Additionally, a Roman soldier of the period employed a large rectangular shield (scutum) and also made use of other weapons, such as a javelin. The style of warfare was very different from what comes in the mediæval period and afterwards.
The point is that, yes, we should not have in mind anything like a late mediæval or early modern sword, or, say, Andúril, Flame of the West, reforged from the shards of Narsil. This is not because a sword of the period was a secondary weapon, but because very long swords were not a thing.