For the sake of the argument, let's assume it is true - there is no metaphysical soul, and all aspects of the self we asdociate with it - memories, character, consciousness, etc... - are the product of electrochemical reactions inside the body. In other words, we are "deterministic" and whatever we do could be perfectly predicted by following the laws of physics.
I think this wouldn't actually devalue the consciousness very much. "Cogito ergo sum" still applies. There still exists a phenomenon called "consciousness" and there still exist entities who can choose an action, given their memories and the impressions of the world they experience.
Technically, yes, humans would be reduced to "mere machines", however machines which are incredibly more complex and nuanced than everything we are capable to build or understand as of now. Also machines who are thinking about themself and have performed all the accomplishments of human history. And I don't think any of this would be going.
The need to consider subjective experiences and well-being wouldn't go either, btw. The need to have a solid ethical foundation and sound morals would be as strong as ever. If anything it could become broader and give more justification for e.g. animal rights. But I can't see anything bad with that.