How do signals simplify Change Detection?

Signals simplify Change Detection because Angular knows exactly what changed and where the template needs to be updated.

#Before:

• Zone.js watched all events (clicks, timers, HTTP, etc.);
• after any event, Angular checked the whole component and the entire tree to find out whether the data had changed.

#With signals:

• each signal knows who reads it (a template, computed, effect);
• when the signal's value changes, Angular updates only the related areas;
• no unnecessary checks or subscriptions.

#To put it simply:

Before, Angular "guessed" what had changed. Now signals report exactly what changed.

This makes updates faster and the code simpler.