2 really really good reasons:

Q) who/what is the largest Linux user on planet earth?
A) Google, everytime you go to google, you are using a Linux operating system runnig on regular everyday available low cost "common" and "generic" hardware scaling from single user desktop PCs to the worlds largest most usage intensive server farms in the world.

Q) who/what is the world's number 2 Linux user on planet earth?
A) That would be the National Security Agency. You know, you taxpayer supported super duper top secret spy agency. So confident in it are they that they even publish their own version of Linux for secure and safe computer use for all. It's called "Security Enhance Linux"
What? You think I'm making this up?
http://www.nsa.gov/selinux/

If those two are not good enough reasons, maybe the US Army working moving 100% of its' systems from hand-helds to weapons systems to mainframes to a Linux OS is?

OK, preacher man is done for the day, it's nice outside, and besides, I have dogs that need playing with....

Y'all HAGD!