It is implicit in the ideas of Owen Barfield, and indeed in many others with an interest in consciousness, that to be aware is a higher state than to be un-conscious. Because to be a psychologically-mature adult is to be conscious of many things that in a child are unconscious. But why is it better to be conscious?
A first answer refers to agency - or 'free will'. Thus the adult may have agency, may control thinking, only because the adult is aware of what he thinks. He satnds outside of, observes, his thinking. By contrast, a young child is largely immersed-in his world, and (in his thinking) more-passively swept-along by it - there is little scope for agency. He thinks - but does not know that he thinks.
But even if agency requires consciousness - self-awareness; why is consciousness better than unconsciousness, why is agency better than being immersed-in and swept along?
It depends what is meant by 'better' - what is being asserted is that consciousness is indeed higher than unconsciousness - as an adult is higher than a child, and a human than a cow; but a young child may be (usually is) a morally-better person than an adult; and a cow may be a nicer creature than many humans.
What then does higher mean? The answer must refer to God's wishes and plans for people: divine destiny. My assertion is that God has various interlinked hopes and plans - some are moral, and some have to do with consciousness.
We can only talk in generalisations, and for some individuals divine destiny may be Not-growing up, and Not becoming conscious (for example, they may die as a child, or may have a mental handicap - and this experience may be a part of their soul's eternal destiny; intended from before mortal life for their benefit, to learn from it something vital). But on the whole, many humans are meant to go through adolescence into adulthood, to move from being unconscious to being conscious; and ultimately to become conscious in the divine way (to become Sons of God).
And divine consciousness is assumed to be most-fully self-aware, because fully agent: fully free.
So, as God is higher than mortal Man; divine consciousness than human consciousness; so higher consciousness is such because it is closer to the divine consciousness. Consciousness can be seen as a ladder from least to most, from (presumably, one average) the (supposedly) 'unalive' mineral world, plants, non-human animals, children, adolescents, sexually-mature adults - and more and more conscious adults.
The degree of consciousness constrains (that is it both makes-possible and also limits) the degree of agency, or freedom; and (I assume) God wants us each, enentually to become god-like in our agency; by choice, and apparently by incremental stages, throughout eternity; but also (usually, but not invariably) partially to experience divine consciousness, briefly at least, during our mortal lives here on earth. (This is theosis - the intention of becoming more god-like, during mortal life.)
In the end, whether we regard consciousness as higher than unconsciousness, freedom higher than passivity; whether we indeed regard thinking as primary, and ultimately more important than behavioural actions, depends on whether we choose to ally and align with God's hopes and plans - or not. Salvation, or not.
First salvation - at align with God's purposes; then theosis - to become more divine in our being and thinking.
As usual for Christians; we find that everything eventually depends on faith, trust, love - the first 'commandment' (to love God) is first for this reason: everything is built-upon it.
(Note: If we do not love God - then none of these distinctions matter. Perhaps only current happiness matters; and if current happiness is enhanced by the destruction of consciousness, or by destroying the capacity to think, to be agent and free in thought - or by being evil, according to God's distinctions ... well so be it.)