Need more explanation about bloom threshold default value

I’d been using 4.14 and I started to use 4.16 recently.

I noticed that bloom threshold default value was changed. (1 to -1) (intensity,also.)

Document about bloom threshold seems outdated.
Explanation in web document is different with editor tooltip.

I’m so confusing.
Are there someone who can explain about bloom ‘new’ default value?
Which value is more proper in PBR?
(I don’t want to stay in “physically correct dream”.)

I also assume that intensity 0.675 has some “meaning”.