Use it for non-work projects, it will help you get a feel for it. I've used it to work on personal projects (creating plans and whatnot) and it's a fantastic way to get comfortable with it.
We are solving design problems. The benefits of cad is that its a universal language that all designers know, and it's a great base point to grow from.
Easy to use and very compatible with other programs (like Sketchup and Revit). Great for quick analytical plans, and very intuitive to use.
I'm not a huge fan of using Autocad in 3d - I prefer to use it in 2d for planning. I do love that it has a 3d feature - it makes exporting and importing into various other programs very easy, but the 3d aspect itself is not something I utilize, just because I find it easier to use in other programs.