Back in the day, Linux was less tolerant of incorrect behavior than Windows 9x was, and would crash, terminate a process, or otherwise surface errors at times when Windows 9x would just keep going until the bugs corrupted memory or similar. Having Linus aboard as a technical advisor, soneone to whom you can say "hey, the CPU is crashing here, what's the kernel trying to do at that spot?", alone, probably would have been well worth the money to hire him.