Send As another user privilege

Hello Experts,

I am trying to find out the difference between allowing a user to send an email on behalf of another user by

1. Setting the 'Send Email as Another User' privilege in the security role 

2. Setting the 'Set Personal Options' for the user as below

Questions -

1. What is the difference between the two?

2. Which is safer option to go with considering that users don't misuse the privilege?

3. Does these privileges apply if we are trying to send an email from a Queue instead of a User? (setting From field of the email to a Queue instead of a User account)

Thanks,

Swaroop