OP- you recognized that you were thinking in HS terms. Maybe some small colleges try to install class unity but college is so different than that.
Many students will enter college with HS credits (and some only grant them after first semester so second semester registration does not get the earlier sophomore times). How long a student takes to get a BA or BS depends on various factors. An example would be the requirements for a major. Other factors are being well prepared for a graduate program. Yes, perhaps a degree could be finished in three years but that could be minimum coursework for the major instead of more advanced courses/research et al. Or perhaps adding a second major.
Your D’s college selection should be about what works best for her. Her IB HS coursework will certainly help at many colleges but being able to take fun electives instead of a tight schedule may be better in the long run. She will have decades to work and can never replace the college years later. Perhaps the school offering advanced standing will not be as rigorous as one assuming most students have AP/IB work in HS.
There are students who need to get through college as quickly as they can for financial reasons. Otherwise even gifted students benefit from being able to take more college courses instead of just the minimums.