Look at armour (which shoes are...kind of, sort of...also). Why go to the trouble to engrave it...often lavishly and abundantly? At first it was probably chicken scratching to to dull the shine...so that it would not reflect the sunlight and give away your position. Then later comes the repousse and the inlay and the rampant griffins.
Or how about the "broguing" on this pair..nevermind the engraving or the rope twist along the bottom....
But in the end what is it? Armour, that's what...and functional, as armour.
PS...you can enlarge that photo three time and it will fill the average screen--to see the exquisite details (for those interested).