What is floating point, and what is the difference between non-floating point (sinking point?). Is it a CPU efficiency issue, or does it somehow affect audio quality? Maybe allows more complex operations?
"Floating point" means that the decimal can move around.
When you have a fixed number of bits per number, that means you only have so many digits to use, to represent a given value.
So to use a miniature example, with 4 digits you can go from 9999 down to 0001, or 999.9 down to 000.1
However, with floating point, you can move the decimal freely, it could go from 9999 down to .0001 - so we just increased the ratio between the highest and lowest value by several orders of magnitude by allowing the point to float. (these examples are in decimal and IRL they're in binary, but you get the idea.)
It's not so much a CPU efficiency issue as a sound quality issue.
@DVDdoug pretty much explained it already, but think about what this means for an audio signal. The ratio between the highest and lowest numbers you can represent is also known as dynamic range in the audio world, so floating point has a clear advantage there. And because it can accurately represent both very large and very small values, you can do a lot more to the audio while adding almost zero noise.
With 16-bits you can't really add a -100dB signal to a -1dB signal. At most, it will add a bit of noise. With 32-bit floating point you can, and still come out with the right answer. This is why it's so important for DSP.