With a standard account you can make the OS to ask you for a pw when you launch at least some exe .
I am placing down my bets that you're referring to running programs with administrative privileges from a standard account, which will provide additional security from Windows by requesting the account password to an administrator account prior to it running the program with the higher privileges (much more secure than just showing the buttons - especially in the case of a Trojan.Backdoor, the attacker would need to know the password).
And a malware that can access high privileges can do more damage
This is very true; using a standard account will definitely keep you less vulnerable to the actions of malware however it depends on the situation. If malicious software wants to access/modify the Master Boot Record, the malicious process will require administrative privileges (from Windows Vista and on-wards - on Windows XP it won't require administrator privileges however Windows XP isn't even supported anymore and it's very vulnerable) as long as User Account Control is enabled.
Unless you have a specific reason to be using an administrator account at all times, it is definitely a wise decision to just work from a standard account and keep User Account Control enabled, providing the admin password on the notifications when necessary - the problem is that many people are uneducated about how the accounts/process privileges work on Windows and/or want full control at all times, even if they don't necessarily need it, which can then be abused by malicious software should they end up infected.
