Hi @neoprodigy. The situation here from what you are saying I picture it like this: I'm 99% sure that on your LG smart tv you have needed to log in for using the spotify app so you can have access to your playlists and everything, right? So your LG smart tv acts like another device like a tablet, phone or computer. These devices normally use an app that asks for spotify credentials, that's fine, but when we talk about a chromecast device, it doesnt have that so people just use it like a streaming device, no need to log in and you need another device to control it, right? The thing here is that premium users have all the features activated so they can cast to any device but, on the other hand, free users have limited features so that's why you only see your chromecast (ready for any user) but not your smart tv.
You're correct, but the problem is that I cant even login on the SmartTV app to access playlist. So basicly I have a new Tv where I cant have spotify (either by the tv app or by casting the phone) and one old tv with chromecast where I can cast spotify.