A big difference in traditional infill and your idea is that traditional materials tend to be all hygroscopic to some extent. SIPs are not, so the weak link is the joint between the timber and panel. It is my understanding that this is where the vapor drive will occur, exacerbated by the differences in materials and complicated by the inability to really seal a shrinking, moving material (green timber) vs. a dry stable material (SIPs).

When using conventiomal materials for enclosure I try my best not to run timber from inside to out, to avoid this issue. Especially with high heating demands and water demands - cooking, bathing, etc. can throw a whole lot of moisture into a house, and depending on season and location and ambient humidoty this may want to work its way out, condensing as it moves.

Of course using traditional methods may work just fine, depending on lots of factors.

But I'm not anywhere near an expert on the science, so consult with someone who is skilled in enclosure systems in your climate.