The digikey costs are more (I quoted qty=1 prices though), its the ratio between the component types which is more interesting though.

I think annoying at 10m is sufficient power to require a 'power' LED, so that shouldnt be hard to avoid in a design I would agree. Annoying in your kitchen however is much harder to eyeball a value for (excuse the pun).

  > I quoted qty=1 prices though

Yet on the unit I linked it is $0.14 per. 2c difference, but hey, that's a full photodiode on Alibaba.

A big part of the assumption that I was making in my original comment is that you're mass producing devices, not treating it as a hobby project. I agree, the constraints are very different in these two settings. A major difference is the cost/ratio of parts to other costs/time. In mass production the price per part is going to approach <$0.01 for standard COTS parts. Same reason Alibaba has them for so cheap (which doesn't include shipping)

  > Annoying in your kitchen however is much harder to eyeball a value for (excuse the pun).

Yes, I agree with this. Though In that setting I think you may be able to dual use the LED. Periodically blink it to detect ambient light. You can be pretty rough with this frequency and your accuracy level. But the best solution is always adding some little POT so it can be adjusted. It adds a little cost and design time, but if you're actually selling products that's very likely going to be a inconsequential amount of time and inconsequential cost.

*BUT* it is something the bureaucrats will be able to look at and say that they need to remove it because at scale it will save "a lot of money." But does it? I'm unconvinced. To me it seems to just make the consumers more upset and annoyed. Sure, you might have saved the company $100k because you are producing 10M units, but I'm pretty confident most consumers would rather pay $0.10 to have that part. The bigger problem might be a Lemon Market type of problem where consumers don't actually know/realize they want such a feature at time of purchase but randomly and intermittently realize it over the next week or couple years. It never gets priority thought because there's usually other things to complain about and well then we need to have a larger conversation about if we're doing our jobs as engineers. Are we actually providing value to people with the products we make? Can we take pride in our work? You may be making something dumb, but can you honestly tell yourself "I made the best thing I could"?

The business people need pushback because they don't care about the product, they only care about the profits. That's part of your job as an engineer. Because your job as an engineer isn't to be concerned with the profits, it is to be concerned with the product. Your engineering managers are the bridge, not you the engineer. And a good engineering manager doesn't fully align with the business people either. Because when push comes to shove you have to decide between either: 1) sacrificing the product in favor or profit or 2) sacrificing profits in favor of the product. As an engineer, your job is to have the latter.