The I in FIRST stands for Inspiration. What is more inspiring, using a free IDE and compiler and a $50 AVR board that anybody can access, or using real tools that are used in industry? At my company, we use both LabVIEW and Windriver/vxworks extensively. While you might get exposure to one of those in college, FIRST is probably the only way for a high school student to be exposed to these professional tools.
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Wikipedia's Notable Products using VxWorks, for example, the Boeing 787, Honda's ASIMO, and the Spirit and Opportunity Mars Rovers.