So, the amount of light that emanates from a smartphone display is sufficient to
significantly disrupt human sleep patterns?
Truthfully, according to that
oft-visited Harvard web page (isn't that the same school that gave us Facebook?), as little as 8 Lux can have a
measurable effect.
Hint: "Measurable" is not the same as "materially significant."
The Harvard article focuses on workplace and household illumination, which is generally far more pervasive and powerful than any TV, computer, or smartphone screen. If you use a computer/tablet/smartphone in a darkened room and dim/auto-adjust the brightness accordingly (after all, when there's little or no ambient lighting, your screens don't have to be as bright), we're not talking about a whole lot of light. If you use them in a well-illuminated room... first job is to attend to the rest of the room's illumination.
However, the Harvard article has spawned more than a few pseudo-news reports that, in more than a few cases, used it to advance the "Using computers and smart phones is bad for you" narrative. Why don't we do a better job of filtering out the blue light of bias when we read stuff on the web?
What keeps me up at night is musing (or fuming) over the folly of my fellow humans. Eliminating the local TV news from my evening diet was very helpful. It's probably also helpful to only draft replies to threads like this during the daylight hours.
Further, reducing blue in my display would totally disrupt the color rendition of my photos, and I certainly couldn't edit photos effectively if I changed the color balance of the display.
Hey, if it makes you feel better to enable this feature, go for it. The placebo effect is real, after all.