I didn't say that, I have script trap as a final fall back but it is rarely used. You could use the Pro paid for version if you feel script protection is essential as that has a Script Blocking provider.
One of the Alwil team has previously said that the web shield provides an adequate (not fail safe) protection against web scripts. This was when asked about what to do as the avast pro Script protection doesn't work with firefox (only IE, Mozilla and Opera I think).
Danger/risk is always present in life and this is no different it is about weighing up risk and the precautions taken and how they impact performance.
Whilst browsing or collecting email, etc. if you get infected then the malware by default inherits the same permissions that you have for your user account. So if the user account has administrator rights, the malware has administrator rights and can reap havoc. With limited rights the malware can't put files in the system folders, create registry entries, etc. This greatly reduces the potential harm that can be done by an undetected or first day virus, etc.
Check out the link to DropMyRights (in my signature below) - Browsing the Web and Reading E-mail Safely as an Administrator. This obviously applies to those NT based OSes that have administrator settings, winNT, win2k, winXP.
A link worth looking at, which is a program removal tool that can remove the remnants of a number of different Norton Programs:
Removing your Norton program using SymNRT, if you do uninstall Norton, it would be worth running this tool to ensure no remnants to effect avast.