You typically gain a tactical advantage by using a melee weapons at near range (at least if you put some focus in Strength). Other weapons that are also good at near range include throwing weapons, pistols, SMGs and sawed-off shotguns.
Unarmed have an AR of Strength + Reaction. Melee weapons have an AR of listed AR + Strength (or listed AR + Reaction for whips) and can typically not be used beyond near (3 meters - or 5 meters with Long Reach). And if they can be thrown into close distance they are often limited to just 20 meters. With a strength of 5 a Knife have an AR of 11 / 6 / - / -
Thrown weapons (and other ranged weapons) have the AR that is listed. Throwing knives, for example, have an AR of 10 / 9 / 3 / - / -