baseline-subdivisions doesn't seem to do anything

[robrecord]

I want my body text to be 16px and leading (line-height) as 24px.

I thought I could set the root size to 16px, and use $baseline-subdivisions: 2, but this outputs a line-height of 2 instead of 1.5, which gives a line-height of 32px.

Instead I have to use a root size of 8px - which is fine, but then what is $baseline-subdivisions for? In what case would it be useful? I thought it would help in my case, but it seems too do nothing.