This is very true! We try to lean hard into the unique strengths of browsers. We have a reasonably sophisticated custom engine managing all the game state stuff

This is very true! We try to lean hard into the unique strengths of browsers. We have a reasonably sophisticated custom engine managing all the game state stuff but the UI is basically just one HTML/CSS file. Implementing this fairly basic UI in Unity would be a headache, especially because of the nightmare that is mathematical function input. We just use Mathquill to solve that problem, the same library Desmos uses for their graphing stuff. Thank you open-source <3