Rupa sits at the midpoint of Samkhya's five tanmatras, denser than shabda and sparsha, subtler than rasa and gandha, and its position tracks a genuinely intermediate role in the elemental sequence. Tejas, the element rupa feeds, is neither the barely-differentiated akasha at one end nor the fully dense prithvi at the other; it is fire, traditionally associated in Indian thought with transformation, visibility and the capacity to illuminate, and the tattva scheme gives that association a precise structural basis rather than leaving it as loose poetic correspondence.
Tejas, fire, is traditionally described as carrying rupa as its own tanmatra and as governing vision, exactly the correspondence stated here from rupa's side. That the two descriptions agree is not a coincidence to be noted with surprise; it is what one consistent system is expected to produce, the same underlying classical claim visible from either direction.
Chakshu's restriction to rupa alone, and rupa's emergence only once shabda and sparsha are already established, together explain why sight, in this scheme, is treated as a comparatively late and comparatively demanding sense: it requires the accumulated density of the third stage of grossening, unlike hearing, which requires only the first and barest.