For me it was a mixture of Boba and the armour itself. The armour was cool, but it was nothing without the aura of menace that Boba gave it in ESB and a somewhat in RoTJ.
But that worked to imbue that style of armour with his...attitude. So every mandalorian has inherited a little bit of the screen presence of ESB's Boba Fett.
Now it is a phenomenon on its own. It's like the red, yellow and black of a coral snake...or the distinctive sound of a rattler, or that flattening hood of a cobra...it means...backoff di'kut. I'm a shabla bad-shebs motherfrakker and I will ruin your world if you cross me.