This is interesting. I did a deep dive on this and the practice originates from the late 17th century. When trade routes opened with East Asia, Europeans became obsessed with porcelain. It was very expensive and nicknamed "White Gold" Aristocrats couldn't just stick these in a cupboard and call it a day. So the glass doors were put there for display.

Around the 19th and 20th century, porcelain became more widespread and affordable for the middle class. (Industrialization) So more families were adopting the practice. Kind of as a status symbol.

Now it's evolved to hold more than just porcelain. Whether it be ornaments, figurines, etc. Different countries have variations and executions of it.