If you plan on playing games, or you might in the future, then the larger size is worth it.
I was constantly dealing with out of storage messages on my older 64GB Apple TVs, so the large storage size was welcomed for me.
When it comes to tvOS games and Apple Arcade games, it only takes about a dozen large games to fill up the storage of the 64GB Apple TV, and only about 6 games for the 32GB models.
If you already have a device for Thread, don't need the internet, and not interested in tvOS games, then the cheaper ATV4K3 would probably be the better choice for you.