Again, why should it be, if consciousness is epiphenomenal with no causal powers, that our conscious experience of the world should be so consistent?

Neanderthals, with similar brains to ours, became extinct, and we nearly did. Dolphins may experience qualia unknown to us and have surplus IQ which they cannot exploit, being effectively limbless. Consciousness may be a feature of brains which just appears when a certain complexity is reached. Lucky for some, unless you’re trapped in a collapsed building or a cyclone.

Evolution does not seem to need consciousness

I suppose you mean to say that consciousness is not a necessary consequence of evolution?

Agreed, no more than an elephant’s trunk is a necessary consequence. Given, though, the undeniable presence of elephant trunks I would expect a responsible zoologist to be able to venture a plausible evolutionary explanation for its existence and additionally I think we can safely say that such a feature was an adaptation that conferred an advantage and was selected for by the usual evolutionary processes.

You seem too close now to presuming that consciousness, the most remarkable thing, is non-adaptive?

Of course there doesn’t have to be. We’re all familiar with psychotic states, drug-induced states, etc. So I’d bring you back to Helen’s insight: the regularity and consistency of the conscious experience of the physical word requires an explanation, and if consciousness is epiphenomenal the only possible explanation - that the effective conscious representation is an adaptation - is unavailable because it cannot have been selected for.