"Being constructed of text characters" is a very loose definition of ASCII art. Not to say it's not visually interesting, but just that it's on the far ends of the histogram of what people think of when they hear "ASCII art".
Personally, I think the fact this is relying on colour for contrast makes this feel more like a shader that quantizes the input into little dots that just happen to be 1 of 3 characters, than ASCII Art. It's a vague border between that and an ASCII shader, and then ASCII art, but there's definitely some measureable distance between those peaks.
(=ᵔᗜᵔ=)
I'd call it an "ASCII-Art inspired shader", but some % of people would look at it and immediately call it "ASCII Art" with no confusion. Some other % of people are also going to scoff at me saying it's "ASCII-Art inspired" at all.
Should mention, I have no issue with this little project! I'm just agreeing with the parent comment that this is just hinting at the limitations of ASCII art without actually working with them, in our opinion. Thinking about art being an important step in appreciating art, and all of that.
How does one learn to write like this? Damn.
Read books. Actual books. The kind made from dead trees.
The more you read, the better you write. That's why our teachers drilled the importance of reading into us at such an early age.