My opinion. While 2 HomePods in stereo sound good however you will generally be better off exploring different options with the caveats being your specific use case.
In a living room (or wherever) for example you can build a system better for film and tv using a receiver that can decode near anything, surround channel separation, works with devices other than the AppleTV, can be equalized for a listening position (not omnidirectional), crossovers, sub that can produce sub bass with a larger woofer and be placed behind the listening position, physical inputs, etc etc.
In the situation where you are in a room that already has 2 HomePods you use for music AND a TV that you only use the AppleTV on AND you are currently using the TV's built in speakers then yes definitely use the HomePods.
While I would recommend the HomePod to most anyone I wouldn't recommend it to someone that was looking for a TV and movie audio.
Consider this, the HomePod is specially engineered for music first and foremost. The HomePod uses horn loaded tweeters to move a lot of air across the room filling a space, it makes the source of the audio (the HomePod) hard to distinguish which is great for music. However film, especially with surround is sending audio to specific channels so the source can be identified as a direction (a car flying past you, an explosions shock wave going through you and echoing behind you, etc).
While I love my HomePods (stereo) that sit near my living room TV however for the TV I use a Yamaha receiver with middle of the road satellites and subs. Honestly (flame suit on) once equalized I feel my Vizio wireless 5.1 in my guest bedroom does better than my HomePods down mixing.
Again this is just my opinion your milage may vary.