Do I see this right, instead of having to have a Gamer Windows PC I can "game" with this part directly on my 4K TV? Is it possible to download games directly from Steam etc.?
Without a PC, GameStream only works via Nvidia's GeForce NOW platform, which is chargeable. I personally have never tried it. There are also games from the Google Play Store that are compatible with the Shield. (There are some fun games, including multiplayer). But it gets interesting when you connect your local gamer PC to GameStream. Then games can be started from Steam and streamed via the Shield. Conclusion: Enjoy the advantages of the console with PC graphics... Without a gamer PC, it doesn't make much sense or will be expensive, so it's better to go for a PS4.