FR Login-Time Vs Unix-Time-Based-Login

Hi Freeradius List, Why someone will use "Unix-Time-Based-Login" why not "Login-Time" FR attribute? Does it offer more flexibility or control over each other. Actually, we want to implement login based on time. i am reading mail archives since yesterday to understand basic functionality of the model. And have also come across where people are talking about both techniques. But unable to know what is better way to go with. Thanks for attending to this material Thanks / Regards RM --