Using the current 3.7.16 Windows version.
The new AI Chat Panel documentation states:
"The toolbar icon only appears when Enable AI features is on in Settings → AI."
This is not the current behavior. The button is visible, regardless of the AI setting.
It was raised as an issue on Github:
And it looks like there was actually an unmerged PR generated to address it:
Either the documentation should be changed to match the actual behavior, or the app should be changed to match the documented behavior.