A "chorus" literally means copies of a sound that vary in "timing", "pitch", or often, both. "Pitch variation" as a Chorus technique appeared way before the invention of delay lines and LFOs. The 12-string guitar is a perfect example, not to mention the extremely common technique of combining two slightly detuned voices in synthesizers. (The audio example below simply detuned two identical samples and involved no delay-lines/phase-shifting at all. Ask a hundred musicians what effect they hear in it and every single one of them will tell you it's a chorus.)
Even with the crude technologies of the 70's, companies like Roland and Eventide were making Chorus effects that altered "pitch" of the delay lines inside. Chorus doesn't require a stable pitch-shift on the delay lines. So we don't really need "heavy DSP power" for it. The early BOSS/Roland choruses were fully analog.
It seems you were trying to make a distinction between a "harmonizer" and a "chorus", with the former requiring a stable pitch-shift, hence the "DSP power". That distinction might make more sense when we are using the harmonizer to generate stable parallel lines that "harmonize" the original line, in other words, several semi-tones apart. In the example you raised, the less-than-semi-tone detuning would have functioned literally as a chorus.
But hey, call it anything you want. I've heard casual listeners describe it as "sweetener", "widener" or "cheezilizer" 😃. The fun is in the actual sound, labels don't matter nearly as much.
Chorus by Detuning .mp3