Google Sitemaps XML Plugin...
 

Is this a necessity for blogs or just a meh if I think of it?

use it yes

and then submit via your g wm tools acct

You don't have to use it but it doesn't hurt, I personally use it on all my sites, takes just a few seconds to generate and submit to GW Tools

why do people on gfy believe its ok to ask for proprietary information?

no necessity, but recommended to use, SE getting your information faster