I would absolutely address it.

Grad school is a test in perseverance as much as anything. And an admissions committee has no way to interpret your past academic performance unless you give them information. Without explanation the committee may assume you lack the academic rigor to make it through their program.

No need to give explicit details about the illness itself (you could even just refer to it as “a serious chronic illness”), but mention it as a means by which to explain the stressors that impacted your academic performance, with emphasis (as you already intended) on evidence of current passions, skills and successes.

Good luck!