The Watchlist (aka “Universal Watchlist”) is built around Plex’ Discover feature. Discover is focusing on finding movies/shows/persons from various sources (based on your preferences). That’s the “watchlist replay screen” you’re mentioning. It’ll show you where that media is available for streaming – from your own server, a shared server or another streaming service.
Hence the 2 steps.
There’s been a feature suggestion to allow playing a video straight from the discovery details page. Though other users have argued they actually want to be offered the Where to Watch options (instead of going straight to a potentially lower-quality local version).
