Everything. Linux (and BSD) do just about everything. Better. It’s time to put your abacuses (abaci?) away, ladies and gentleman. Linux is everywhere. Linux is the future. THE FUTURE! Ok, I guess there’s no way I could know that for sure… Or is there? No. No there’s isn’t. Sorry.
I think there’s a notion that professionals tend to run macOS and/or Windows. That does seem to be the trend these days. But desktop Linux is getting better all the time.
Linux and BSD are great for business
According to W3Techs 67% of all websites where the operating system is known are running Linux, BSD, or some other variation of Unix, as of August, 2016. Businesses like Google, Netflix, Sony, and Apple, among many others, rely on some variation of Linux or BSD. Netflix runs FreeBSD on its servers, streaming in excess of a billion hours of movies and TV every month to more than 30 million users, representing one third of the total peak downstream internet traffic in the United States (we’re talking petabytes of data). Companies like Apple and Sony use FreeBSD for operating system development. Apple’s iOS and OS X rely heavily on code from FreeBSD, while Sony runs a modified version of FreeBSD on its PlayStation 4. Google uses a modified version of the Linux kernel for its Android operating system. Android is the most popular mobile operating system in the world.
It costs nothing and runs great on old hardware
Linux turns that beige piece of garbage computer from yesteryear that’s been hiding out in the closet into some kinda awesome, highly functional, purpose built machine. For free. The only cost is time and expertise. I’m not gonna lie, this kind of project can take a lot of time and a lot of expertise. But if you’re someone who knows a thing or two about computers, this could be a great investment of time, great for your wallet, and great for the environment. Everyone wins.
Even very old hardware can be rendered usable again with Linux. Arch Linux has very modest minimum system requirements. Pretty much any old i686 system with 256MB RAM and about 800MB of free disk space should do. The i686 CPU was introduced in the 90s. We’re talking really old here.
Security, stability, reliability
OpenBSD, famous for originating OpenSSH and known for its security, uses the slogan, “Only two remote holes in the default install, in a heck of a long time!” Linux, and BSD operating systems especially, tend to be very secure.