Aliens don't take eyes or noses. They don't take ears, either, which are not only sensory organs but help us with balance. They don't take external genitalia, hard-wired as it is into our biology.
Something that would make the Predators live longer would likely have no use to an Alien, which we haven't ever seen reach old age and die.
Scar's dreadlocks were set on fire, and he seemed perfectly fine with the whole thing.
If there were important, no intelligent species would keep them flopping in the open unprotected. They wear armour over their face and body ... yet neglect this seemingly indispensable organ flopping around their head?
There's nothing saying they're tubes either - They don't seem hollow.
At the end of the day there's nothing they could be that would mean an Alien should take them.
Except people don't bother thinking and just say "Well dur it lookz kool".