IMO they are reef safe I have never had a problem. And not they dont eat acros. Post some pics of the acros and maybe some onecan help. I know they can irritate them.
they dont eat them, they tear up some flesh nesting in it but thats their natural behavior. If you have alot and large colonies might not be a big deal. If you have a few 3" colonies well clown gobie probably isn't the best choice.
I don't think they are boring but are better suited for the smaller nano tanks. They are just so small and in bigger tanks they often get bullied, starve and die.
They are colorful and very cute though.
They along with the sexy shrimp IMO are best in small nano tanks.