Total newbie query here! (be gentle)

as a total newbie I hear a lot about why you need a powerful rig to create your own things such as scenes or characters through Blender (or any other program like this) to eventually use in something like Daz. So… why is this? I mean the specs I am told I am needing to eventually create such things on my system are VERY expensive such as EXCESSIVE amounts of RAM and a high end graphics card etc.

(told you it was a newbie question)