Yes, These are Newbie Qs. Why use Ruby? Why use Rails?
Foremost I use both because they work well and get the job done with less effort than the alternatives I have used. The buzz suggests that I am not alone in that opinion so there is a broader base of experience also making that choice.
I personally like Ruby a lot (being an old Smalltalk guy). And Rails is very well designed from what I have seen so far. There is a learning curve as with any tool. Both ruby and rails have a definite view of the world that is not exactly the same as anything else. Unlike many frameworks in Rails SQL != BAD. Rails provides a thin layer above SQL to make common operations easy, but makes no attempt to hide from SQL. The duck typing of Ruby makes all this much easier to work with than a system like Java where all the details must be worked out in advance and the slightest deviation makes two objects incompatible with each other.
Michael
Here is a presentation I did on this subject...