Geoscience data often requires a spatial context for proper interpretation
Utilization of maps in the classroom can spark student interest and improve understanding of spatial concepts commonly found in the geosciences (see for example, Gutierrez et al. (2002)).
Modern computer-based GIS presents the ability to develop, analyze, and interpret multiple levels of spatial data, particularly traditional geological field data, in a quantitative way.
Map creation and quantitative interpretation skills are important for those who intend to pursue geoscience or other scientific careers
Quantitative and spatial analysis skills developed through the use of GIS in the classroom can also benefit for students as they participate in societal discussions of scientific matters.
Practical Reasons:
Utilizing GIS within the classroom can be done without high-level hardware/sofware
Numerous websites and vendors provide free and for-pay GIS data/mapping utilities
Shareware/freeware GIS software packages are available
Consumer-grade GPS units provide inexpensive means to collect spatial data during field trips