Re: Like grep? sed? awk?
I don't think you read the doc you link to. It's nothing like grep. It enforces the presence or absence of the lines - adding required lines if not found, deleting lines that the file must not contain.
You could do this with sed or awk, of course, but the point of this is to underly puppet/cfengine like functionality that MS is building into it's management tools. Puppet and friends are awesome products, and the model of managing configurations like software to be progressed from dev to test to production is a good step forward, but current tools are focused on devs in that they work in a programming kind of methodology and need a brain used to working with code to use well. Depending on what tools MS wrap round this engine they could address the market of admins wanting to gain the advantage of dev ops before the existing tools do.