Yes Andorid box provide features as in sony , sometimes more than TV manufacturer. Since its a standalone box it has more potential to play the content than TV ,and you will have more options to intall new features and Apps.
Android built for Tv is very lightweight since their cpu and memory are limited. in case of android box memory and cpu will be more.
Of course we need to spend extra to get android box , but dont get the chinese android boxes , go with any standard android box like Nvidia_Shield console built with android os..etc.
Secondly nothing wrong with Webos ...now a days all tv manufactures providing popular apps , like Netflix ,hotstar .. etc to be installed with smart tvs. You may wait for sometime whether LG releases updates to install these apps. Then you can pick up android box if not so.