I wish Symantec could give us sometime web protection without any extension and toolbar in all supported browsers. And that's why it better:
1) Now we have some restrictions in Firefox that don't allow to use web protection properly. Submiting suspicious sites for analyzing in Symantec don't work if you use only Firefox. Blocking fishing sites by heuristic analysis (Scam Insight) don't work also. That mean that you could face with unknown in Safe Web site and just lose your personal info.
2) It would be much easier for Symanted to introduce web protection in that way, because you don't need to optimize this toolbars and extension for each browser. Seriously, look and Kaspersky. They have 5 extension before in Firefox, now they have only one and it doesn't concern to web protection - it contain virtual keyboard, tracking protection and antibanner buttons. Yes, that means that you have to put your certificate in all browsers but I think it is better that optimize some extension after each browser update.