In general a guy who is somewhat larger than average by means besides obesity is stronger than a normal sized human and more dangerous in a scrap, either unarmed or armed with melee weapons. On the same note larger animals are more dangerous individually than smaller animals. Really tall humans that are more than 2 meters tall usually have major health concerns, which get more and more pronounced as height increases. Individuals more than 2.3 meters tall often have to walk with canes. Never the less, these fine details of medicine were not well known in the Bronze Age and people loved to embellish and embellish on embellishments in storytelling. As such it is little surprise that Giants, people who are of a much greater scale than normal Humans, are so common in mythology.