Soundiiz (or similar) integration certainly gets a thumbs up from me as a stop gap and is far better than having no easy route to automated playlist syncing.
But for a (premium) music library management platform, this feels like functionality that should really exist within the Roon product/offering itself, at least as a basic level of functionality (*). How many extra monthly subscription do we all really want to be paying for.
(*) not suggesting Roon incorporate all of Soundiiz features and support such an exhaustive list of streaming platforms. But it feels like there’s a small and sensible subset that would fit nicely into Roon itself rather than needing to rely on a 3rd party platform.