When I graduated, my first project was to make a UK LED based wait indicator. The problem was, the standard specified "white" light. At the time while LED's where made using UV LED's and phosphors was used to make it white. This meant that for 100 LED's, the coat would be about £100 just for the LED's. In the end we got the specification changed to include a yellow, (we showed that a tungsten light bulb running at 45vac is very yellow anyway, so it was more a correction in the spec than a change)

While the video at 28:09 asserts "virtually no downsides" to LED bulbs, it overlooks a crucial aspect: light quality.

The quality of light is a critical parameter, typically measured by CRI (Color Rendering Index) or the more comprehensive TM-30 metric. Incandescent bulbs naturally excel in this regard, offering what is often considered 'optimal' light quality. However, replicating this with white LEDs remains a technically complex and costly endeavor.

What a lovely story and well-explained!