I agree. A couple of years ago I was asked to design a circuit that could read a voltage, perform a few calculations and multiply the result by another voltage

I agree. A couple of years ago I was asked to design a circuit that could read a voltage, perform a few calculations and multiply the result by another voltage and create two phase-shifted signals from that multiplication product. It was a simple design in that it could be reduced to high-school trigonometry. However, finding an efficient implementation was not trivial. After spending a lot of time looking at parts and considering multiple approaches, the simplest answer was to do the slower aspects in the CPU and use a 4-quadrant Multiplying Digital/Analog Converter (MDAC) to do the heavy lifting (signal multiplication). ISTR that doing it all digitally would have required a processor with at least a 40MHz clock and probably a separate 200MHz clock to implement a 1-bit DAC. And I would still have needed extra circuitry since one of the inputs (and both outputs) could swing +/-10V. Not to say that the all-digital approach wouldn't have worked, but the development cost would have been overwhelming for something that probably won't sell more than 200 units or so. By using an MDAC and a couple of opamps, the design was reduced to an Arduino "shield." Have to say, it works pretty damn nice :-)