It is not just UAC though - when your daily driver is NOT an adminsitrator then how is most ransomware or malware or whatever going to run and install itself in

It is not just UAC though - when your daily driver is NOT an adminsitrator then how is most ransomware or malware or whatever going to run and install itself in the first place? UAC still pops up whether you use an admin account or not - it just requires the admin password when you use a standard account (which is, of course, still more secure). But the real advantage is that the account you are using does not have those admin privileges in the first place. The other big advantage is that if this account is compromised in anyway (say if you used the same password to login to Chrome and Windows on your standard account) the hackers only get the password to your non privileged account. Of course this can be mitigated as well by really good password policy but I find for the average user they often re-use passwords and separating the two accounts forces them to often re-use the one that matters least.