I noticed this when I just started new college applications today. I’m just curious if there is a purpose for BU in doing so.
Probably because they get some students applying mostly to other Apply Texas schools and other students applying to mostly to other Common Application schools. Accepting either application allows them to get applications more easily from both sets of applicants.
Probably for the same reason other schools migrate to the Common App: to enlarge and broaden their pool of applicants.