Having seen the horror shows that some people did to their computers. It is much better. Least priv is a decent thing to strive for. You want to reduce the attack surface. By giving people root you basically make the attack surface your entire computer. I am not going to make the trojan writers job easier.

Also as I have gotten older I also realized that I make mistakes too. Running as least privs reduces the fallout to 'i have to restore a few files' from 'i get to reinstall the whole computer again'. UAC/notroot are tools to help you. You can discard them. That is fine. Not going to judge. I am saying most people it helps them. Not that it matters much anymore anyway. Most of the people who did these silly things to their own computers have moved onto tablets.