I think that 1/8"seam is recommended for mini quilts, and also recommended to be pressed open. That makes sense to reduce bulk.
On 1/4" seams I will automatically press to one side.....just because I have done that for these many years. However, lately, I have opened some seams when working a block that seemed to be too bulky with side seams.
There was a time the side seam helped to keep the batt from bearding, but with today's better methods that is probably not necessary.......
As most everything else, we each do what we find works best for us individually.