One benefit of "clarity" is to communicate to the reader, of course. Another, huge, huge benefit, though, is the possibility of communicating better with one's own self. To make an idea clearer is to explain it to oneself, in the first instance. The process of revising a paragraph for "clarity" is a process of thinking through the ideas better, not just expressing those ideas more elegantly.

One way to do this is to simplify the ideas themselves. Sometimes this works--there may be a level of complication that is simply not relevant, or not as interesting as you thought it was. But the main goal is to present the most nuanced possible view of things--we are scholars after all. The subtlety is itself the goal, not some obstacle in the way of the communication of simplistic information.

I'm not saying clarity should trump all else, but it does have its benefits. It can communicate a sense of modesty and friendliness. It tends to get along well with elegance too. In an immature scholar, lack of clarity is associated at times with the mimickry of theoretical texts. Clear writing tends to be more "one's own voice," all things being equal.

Clear writing can be quite clunky, as in this blog post. So this particular value is necessary but not sufficient.

I've had to reject a few articles recently that were beautifully and clearly written. Hélas.