I'd imagine it's pretty much impossible to make a crypto system which doesn't introduce unreasonable latency/battery drain on low-end mobile devices which is al

I'd imagine it's pretty much impossible to make a crypto system which doesn't introduce unreasonable latency/battery drain on low-end mobile devices which is also sufficiently difficult for scrapers running on bleeding edge hardware. If you decide that low end devices are a worthy sacrifice then you're creating e-waste. Not to mention the energy burden.