The expected use case is you use your own bouncers that you host on other machines like the normal load balancer function does in an reverse proxy program.

Sure if you use loadbalancer to use other bouncers as an private bouncer. But if you use it in public bouncer, You may found a lifehack here. Sure. I won't blame on that. But chances are the upstream bouncer admin will notice the sudden high load & traffic, then starts blocking your public bouncer IP, which then completely ruining your users experience that were using your bouncer.