Reading blueprints is important in architecture and allied trades as well. Any profession requires some amount of visual information or mapping. It is heavily used in design fields like architecture and building construction because any idea to be implemented requires instructions on how to build the design.
At any point an instruction manual will always carry some graphical explanation of instructions. Architectural design is the same, but relies heavily on graphical information to orchestrate and document process, not just for building houses but for other problem solving issues like scheduling or general concept mapping.
Graphical plans are written without words, as such constant exposure to drawn plans will engage a student or individual, in constant learning or reorganization of ideas from experience and personal vernacular.
Being able to read plans fast is important for the building trades as some drawing conventions differ from others. Like any language it requires constant drills to develop fluency.
Working in groups also overlaps with reading plans if not in projects but also in exchanging ideas. Learning to find workflow with other designers, students is vital to any collaborative work or project. In this way, a plan reading exercise helps students and designers alike to constantly reshape their personal and collective ideas about blueprint reading.