I saw some links in this thread, but they look like marketing materials to me. Aliasing is more or less solved problem, and the claim that running a DAC at 24 MHz makes it “better” in any measurable way seems ridiculous at face value. I don’t know what is actually going on, but as far as I know they’re just taking a delta-sigma DAC and talking big talk about the oversampling. In truth, oversampling here is usually just a boring engineering choice where you trade off bandwidth and SNR.

If the Novation Peak is running an 8-bit DAC at 24 MHz, they might be making it perform equivalently to a 16-bit DAC at 48 kHz—note the ratios. This is not anything new, it’s just something old that happens to have big numbers in it.

It's the extreme low latency, while yes you can do a lot with just a pi, still we are talking around 20ms latency. With this setup we are talking about digital hardware synths running at sub 2ms latency.

The way I understand it is that you can do a lot of DSP related work in the FPGA such that a Microcontroller board can do more sophisticated stuff than otherwise.

For makers and hobbyists, the power efficiency is less of an issue, in general. But FPGAs may enable a battery powered application where it wouldn't be possible otherwise.

Also, for learning advanced FPGA programming, audio and DSP seem to be a fruitful playground.