In this font landing page "small caps" and "capitals" are being differentiated. Why? What is the difference in appearance and utility?
See for example this font that includes both capitals and small caps.
Typically a font’s small caps are designed to rise up to somewhere around the font’s x-height (or a little higher). Regular capitals rise to the full cap-height. For example, in Adobe Caslon:
Sometimes the small capitals are just scaled down versions of the capital glyphs, but on a well-considered and complete typeface (like in Adobe Caslon above, or in the Franchise Bold font you referenced), they’re often slightly different shapes, so that their weight and thickness is consistent with the rest of the typeface.
That way, you can set small caps right in line with standard glyphs without the capitals just looking like a smaller font size.
Wikipedia, 'Small caps' page:
In typography, small capitals (usually abbreviated small caps) are uppercase (capital) characters set at the same height and weight as surrounding lowercase (small) letters or text figures. They are used in running text to prevent capitalized words from appearing too large on the page, and as a method of emphasis or distinctiveness for text alongside or instead of italics, or when boldface is inappropriate.