"Plainly put, that's not my definition of "working".

In your example the speed of the animation depends an the content height, while a "working" solution should have a constant speed, like the max-height solution. It is not really nice to see different drop downs open with different speed.

Thus, excluding the magic number, the max-height solution is better than the one proposed by you according to your definition of "working", because it provides constant speed of content unfolding. On the contrary, by my definition of working, it depends on what you want to achieve, since every solution has pro and cons. I would use a JS solution as a last resort.

Bout you are monochromatic, and just able to put things in only two categories: good and bad. Have you ever noticed that between black and white there are all the colors?