How useful are multiple bachelor degrees and minors?

If you’re thinking archaeologist, then a minor in an appropriate language (Latin, Greek, Hebrew, etc) would be helpful.

A lot of anthropologists today are “modern” anthropologists in that they study subcultures in contemporary settings rather than isolated villages in the rain forest.

Rather than collecting degrees/majors/minors, it might be more effective to pursue research opportunities and internships in each field in order to help you decide which area you’re most passionate about pursuing.