Do Web Workers Increase (or Decrease) Security?

Question

Do web workers alleviate or intensify any of JavaScript's and the Browser Environment's known security issues?

Answer 1

According to the Mozilla Web Workers Security Review:

• Workers execute in a tightly controlled sandbox.
• No access to Components or other global JS components.
• Only basic JS (Math, Date, etc.), timeouts, XHR, and importScripts.
• Script loading is subject to the same restrictions as on the main thread (content policies, same origin restrictions, etc.).
• XHR uses the same code as the main thread.

These answered all the security considerations I had.