Why don't upper case numbers exist?

Question

Capital letters add a lot to text in various ways, for names, brands, emphasis (although capitalisation for emphasis is frowned upon)Why then, are there no upper case numbers?

Answer 1

One would be hard-pressed to find capital and miniscule numbers in an language. Our modern numbers come from the Hindu-Arabic, which had no lower-case numbers. Only the Roman number system had lower-case numbers, as we've seen in books and outlines in manuscripts and research papers and dissertations.