I didn't ask for conjecture or headcanon, I'm saying prove it.
You just contradicted yourself as it is, "they don't need to, oh but they have all this other stuff they don't need based on that same logic too". Which is to say, you're just guessing they don't have those particular things despite having these other things they also wouldn't need based on this premise, ergo, it's not an argument, burden of proof is on you.
Your argument isn't sufficient, they can hear, yes? Thus, prove they do not have any sensory organs, they have a brain right? So they have nerves do they not? So why wouldn't they have sensory nerves too? As just one example. You need to prove this, and prove it now, otherwise it's not an argument, end of.
Like "they can see", yeah they got eyes dude, which fyi the stun grenades at that level would probably cause temporary blindness and sensory overload, regardless of regeneration btw, but that's beside the point.