My opinion is just an opinion, but it's based on what i recall from previous forum posts or conversations with Admin over the last 18 months or so.
1. When the sim takes stadium factors into effect, it only looks at the +/- factor. The three digit decimal factor has no effect on outcomes. I am not certain if the three decimal park factor is based on the +/- or if the three digit decimal park factor is calculated first then the +/- is derived from that. That is something that Admin would have to confirm, but I don't care too much about it since it doesn't affect outcomes.
2. While the three digit decimal park factor does not alter outcomes in HBD, I don't think the three digit decimal park factor is just for looks. I do think it can be helpful if it's accurate, but only in unique situations. If you look at the
old list and compare two completely neutral parks like Charlotte and Little Rock, one three digit decimal is .983 and the other is 1.021. So if you look at just the three decimal park factor, you could be fooled into thinking that Charlotte is a pitchers park and Little Rock is a hitter's park, but since the three decimal park factor doesn't matter, that's not the case. So the three decimal park factor doesn't help in that situation. However, where it might help an owner out is a park like Kansas City. Many folks might look at the +/- of a park like KC and think it's more of a pitcher's park because it suppresses homeruns, but when you look at the three decimal park factor, it is actually leans as more of a hitters park. So I think, in certain situations, the three decimal park factor is useful.