It changes security alot!. Because you working on user who can become root.
If you working on limited user rights, and if this user will be compromised, the attacker will have harder time to get full system control.
Linux is multi user system, this gives it security because you don't need to be doing all stuff as root.
This makes no sense what you just say. Using admin account for administrative things is counter... ?
Security comes from compartmentalization. It's more safer to use limited user for all activities except admin tasks. But when we have sudo we loose this multi user security feature...