Why does battle high exist?

[RyuDragnier]

I don't get it. Every single game does this.
Shooters with killstreaks.
Fighting games with guages.
Racing games with drifting.

You don't reward players for being bad, that's like if a shooter gave someone on a 20 death streak a tactical nuke so they felt better, or a racing game gave you a free speed increase because you were in last place for 5 minutes.

You don't buff people on killstreaks either. Which is what this game does.