The compartmentalized wooden box used to store movable type used in letterpress printing, became very popular years ago, and maybe they all were leftover letter cases after the modern techniques took over the process in the books and newspaper printing rooms.
When loose letters (types) were used to put together words into lines, and lines to pages, the translator used a compositor to store types (letters, characters and symbols). The box usually consisted of two shallow tray or trays with specific location for the types. The box was divided into two parts, the lower for most-used characters (hence the name lower case), and the top of the lesser-used characters (upper case), such as uppercase.
Johannes Gothenberg was the first to use Movable types in the 1450s when making his 42-lines Bible. Gutenberg refers to the process as 'Das Werk der Bücher': the work of the books. He had invented the printing press and was the first European to print with movable types. But his greatest achievement was arguably demonstrating that the whole process of printing actually produced books.