- what is the difference to the tyre whether the braking is engine braking or normal braking ?
I am no expert in this topic...
I would guess that there isn't a big difference to the tires, what difference there is would be possibly the abruptness of the braking. For sure it would be that engine braking would be 100% rear, where normal braking is almost all front. This would tend to shift more wear to the rear tire- and the rear already takes a lot more wear than the front (as evidenced by so many people having to replace two rears to one front).
Now, engine braking does affect the engine, transmission, and drive. I suspect the engine won't care much, but the transmission and drive probably will see significant additional wear. And some systems aren't designed as well for this "reverse" torque going through them. As for if it really matters on the Concours, who knows. Of course, this engine braking will also reduce wear on the braking system- pads and rotors mostly

Like [I suspect] most experienced cyclists, I use a combination of engine braking and braking on most stops. I believe it even recommends this in the Kawasaki owner's manual.