Is it ever more appropriate to use "cognizant" over "aware"?

In every sentence I have ever read that uses the word "cognizant," the word could easily be replaced by "aware." On top of that, "aware" sounds much less pretentious and to-the-point.

Are there situations or contexts which lend themselves more to "cognizant"?

Personally, I eschew utilization of an over-augmented, trisyllabic linguistic unit like "cognizant" to express a paradigm when diminutive constructions are accessible.

I applaud you for NOT asking, "As 'cognizant' is longer and sounds more intellectual than 'aware' while it means pretty much the same thing, is there ever a time when I should use 'aware' when I could say 'cognizant' instead and sound so much smarter?"

On the serious side, I think the only time I've used "cognizant" was when I was doing contracts for the military and the word had a specialized technical meaning: a "cognizant activity" was the agency or department responsbile for some contract or task.

While a simple dictionary definition doesn't make this distinction, to my mind "cognizant" implies a true knowledge about or understanding of something, as opposed to simply having heard that it exists. So "Bob is aware of calculus" says to me that he knows it exists. "Bob is cognizant of calculus" tells me that he really knows something about it.

You might use "cognizant" for the same reasons that you would use any synonym: to avoid using the same word several times in the same sentence, to avoid unintended rhyme, to avoid using a word that sounds too similar to another word you have just used, etc. For example, if I started to write, "Are you aware that Wally is aware of the need to be wary of Warren's ward's housewares?", I think I would start looking for alternative words, and replacing one of the "aware"s with "cognizant" would be a possibility.

I would consider it appropriate to situations where:

1. You are trying to sound pretentious.
2. A meaningful distinction exists between awareness and cognizance, i.e. things that are registering in your perception vs. things you are actively thinking about; for instance, I could see such a distinction arising in attention studies.

Aesthetic considerations sometimes favor cognizant over aware.

Poetry ensues:

I met a little ant
that was crawling up my pant
right by the stain on my knee.
I knew its locale,
and its direction as well,
but was said ant cognizant,
even a little, of me?

Aware would wreck the rhyme and meter here.

I will be free as early as 7am, but that doesn't mean I'll be cognizant.

is more appropriate than:

I will be free as early as 7am, but that doesn't mean I'll be aware.

furthermore, more professional, more playful, and less self-deprecating than:

I will be free as early as 7am, but that doesn't mean I'll be functional.

in addition to being more accurate than:

I will be free as early as 7am, but that doesn't mean I'll be conscious.

and more semantically harmonious than:

I will be free as early as 7am, but that doesn't mean I'll be mindfull.

Merriam-Webster's definition of cognizant places emphasis on personal experience:

: knowledgeable of something especially through personal experience

I would say that use of cognizant is mostly prevalent in legal contexts.