I am new to solidworks so pardon my ignorance if this doesn't make any sense.  I have been using weldments and I like the idea of the 3d sketch and how things get updated.  I don't understand why there isn't a flat metal choice?  Sometimes I will add plates to my design and while I know I can draw them as a part and then create an assembly there are a lot of advantages to using the weldment features instead of going the separate part route (changes sizes on the fly, cut list info, and the end treatments just to name a few. 

By flat metal I mean plate steel like 4" x 0.5", or 3.5" x 3/8" things like that you can order from steel suppliers. 

I feel like I must be missing something because I am unable to find flat metal weldment profiles online.  I know I could draw them, but I am confused why they are not already in the ansi metal weldment profile list or someone hasn't created one already.