i completely agree. i've tried both, and without the plugins is better. if you put the code in the right spot, the ads will be created automatically everytime you create a post - depending on where you want the ads of course. i put ad blocks at the top of the post and those ad blocks are created automatically.
yes, just for wordpress webmaster, not in www.wordpress.com. Everything with Google Ads must be follow TOS; not against the rules.