Thanks for the feedback. We’re in the midst of updating various documentation and asset store information to reflect Havok Physics for Unity’s exclusive availability in Unity Pro, Enterprise and UIC upon release with ECS for Unity 2022.
From a technical perspective, Havok Physics for Unity and Unity Physics are both great Physics offerings, wherein Havok’s stateful implementation enables more stable physics behaviour in large worlds and complex simulations, while Unity Physics enables GGPO/Rollback multiplayer genres due to its stateless implementation, and also great for most genres of games.
In the upcoming initial release of Havok Physics for Unity, our priority is to make sure our users who are most likely to benefit from Havok Physics for Unity have easy access to it and are provided with greater embedded value with their Pro+ subscriptions (previously Pro+ users had to pay $20 per month for the experimental package). We will continue to evaluate the uptake of Havok Physics for Unity upon release to understand how users are interacting with it, whether there’s significant demand for it in Free/Plus tiers and ultimately, drive for better user experience.
I hope that helps!
edit: Corrected a mistake above, where Unity Plus was stated, instead of Unity Pro.