Moonlight can sometimes be useful maybe, but i think sub lumen mode (even lower than the average moon mode) is just a hype because a few people keep begging for it while the rest of us have no practical use for it, especially in an otherwise powerful 1000 or more lumen light.
And so another useful mode is often sacrificed for the sub lumen mode, causing overly large jumps in brightness.
Also you often can’t even see if that the light is turned on in sub lumen mode when you’re not in complete darkness.
And who reads a book with a cigar type 21700 or 18650 light anyway?

But that’s just my opinion as a flashlight user in real life situations.
I was a big fan of the LD25 3 mode driver.
Just 3 well enough spaced modes (and a hidden strobe) suits all my needs for a 10 Watt light.
Yes, for a 20 Watt light an extra lower mode would be good, but not lower than 50 lumen.

With BS i also mean configuration mode with too many options and things like that.
Not neccesary when you have 3 or 4 well spaced modes from 50 or 100 lumen to maximum output.
But again, that’s just my opinion.
But it’s annoying that a driver with well spaced modes is hard to find.