It isn't so much that analog is expensive, but digital gates are really really really cheap, robust to noise and interference (except for designed-in noise like

It isn't so much that analog is expensive, but digital gates are really really really cheap, robust to noise and interference (except for designed-in noise like floating point quantization error), and often field-configurable/programmable/etc. This isn't entirely fair, but: ANALOG: a TL082 op-amp has ~30 analog transistors and costs $0.10 = $0.003 per transistor. DIGITAL: a GeForce 2080 Ti has ~18.6 billion digital transistors and MSRP $799 = $0.00000004 per transistor. The kind of analog computation I'm demonstrating requires that the 4 BJT transistors be well matched to each other, which can be expensive in terms of silicon die area. Digital computation doesn't require well-matched transistors. It requires that each of the individual transistors is just barely good enough relative to some absolute threshold. (And if it doesn't, we'll just clock the chip slower!) Of course, there are tons of critical analog circuits in your smartphone. The RF interfaces for cell/wifi/BT, the capacitive touchscreen, the cameras, the battery management system, audio, display... But given the cost difference and other advantages, it makes sense to do only what must be done in the analog domain, then convert to digital and do the rest.