DD14 and DS17’s High School had an Cambridge AICE program, however, in the 9th grade, all of the AICE kids take AP human geography. It seen as a good introduction too more rigorous classes (for all of the reasons listed by @toowonderful ).
Both IB and AICE have started to roll out middle school programs (the state of Florida is experimenting with both). I’m sure the College Board thinks this is a “growth area”.