I really like how the devices they build are made like early electric devices: often mounted on wood, more ornate than they should be, while also still mostly very functional.
I also really like how they take a principle and make something from it with own research and development. It's like the textbook example of a 19th century inventor.
And, given that this is fully DIY (aside from the screws maybe), it's super impressive, even though the sound quality isn't very high (but it does have an aesthetic quality, imo!)