That's just changing a convention, not a tuning in the sense talked elsewhere in this thread (how we divide notes), but "what our starting frequency is".
A=432 and A=440 is just as arbitrary. They just had to pick something so they would all match.
The main difference is that 432 is associated with a set of new age, healing, "universe", etc. BS claims in certain "spiritual" circles...
In baroque music, ~430 and 415 are also very common since they are thought to be the historical pitches of "A"
That's so low, it's more like playing the piece a three semitones lower than an alternate choice for A4.
If the piece was in A, it would be more like playing it in F# (while still using A=440).
(Of course if you did that, the "sweet-spots of 12TET and its off-notes would be different, than if you played with A=360)
Tuning your orchestra high was sort of the 19th century equivalent of the modern loudness war. The problem is that orchestras tuning to ever higher pitches meant that singers had to sing higher to match, and it was putting serious strain on their voices, which can easily lead to injuries.
Having some sort of agreement setting a standard was just something of an "enough is enough" sort of moment. It just amuses me to no end that this was achieved by writing it into the Treaty of Versailles, of all things. We're settling a freaking world war, so let's make sure we settle the issue of orchestra pitch as part of the treaty.
Or I might be wrong, I know nothing about music[2].