User and device signal
The "Programmable Taskbar" will only apply to new accounts or first logins, and Microsoft plans to tailor the layouts "based on user and device signal" to cut down on "perceptions of bloatware".
Leaving aside the absurd suggestion that Microsoft will do anything to reduce bloatware, I really do not want them auto-magically sticking things on my taskbar. It's the one place in Windows where I'm in control, and they can stay out of it.