Anything a console can do, a PC can do better.
If you don't want to shovel hundreds of dollars into a giant metallic mouth or try to figure out how to install a new motherboard or deal with nail-bitingly frustrating problems that come with PCs, a console just lets you play things in a neat, convenient little package.
There are a couple more things to it, though. For example, to be a game developer on the PC, all you really need to do is learn some programming or do some flash work. SDKs and map editors also make modding an experience almost completely exclusive to the PC. On consoles, this would be a lot more complicated, and the level editors there tend to suck. PCs have the tools for an indie gamer.
Perhaps this argument would have made more sense back in the day, when the hardware for gaming consoles and computers were fundamentally different. Nowadays, consoles are nothing but specialized computers. These days, it's pretty obvious the pros and cons of PCs and consoles.