Proper insulation is a very complex topic. What I've learned throughout my career is that you never stop learning. As products change and more studies are done, the best insulating solutions change as well. You will want to explore this topic further on your own. Don't rely on one source of information and be cautious about who is providing it or did a study, (independent studies are generally not invested in any particular manufacturers products).
As you will come to understand, insulation is as much about moisture transference as it is about temperature control. Temperature control is the thing humans readily notice while moisture control is what impacts the longevity and integrity of building materials. It also plays a major factor in the healthiness of the environments we live and work in.
All insulations create a dew point where the temperature difference from one side to the other causes moisture to form. It is always somewhere inside the product. The advantage or disadvantage of different forms of insulation is where the moisture can condense. As an example, with closed cell spray foam, while the dew point is still internal, there is no place for the moisture to condense so it happens on one side or the other. That makes it much easier to prep the wet side of the insulation with the proper moisture barrier(s). In contrast with traditional batt insulation you may have encountered the common problem of insulation that has become saturated with moisture and rendered useless.
This does not mean that one insulation type is necessarily better than another. They all have there best uses and require proper preparation and installation.
You can't stop moisture from forming and needing to travel somewhere. Sometimes you need to create a tight seal and other times a way to breath or wick the moisture away.
Remember, wood exists as one of the best natural moisture controlling substances on the planet. It can tolerate a very wide range of moisture levels. Wood does not need to be kept 100% dry (and shouldn’t). As long as you create a way for it to regulate it’s own moisture content through correctly designed moisture barriers, ventilation and hvac systems all is well.
Below is a study published by the LSU AGCenter Forestry Laboratory. This is a good example of the type of information you will want to look for as you continue to understand the best use of insulation products.
