Scene Partner Reader vs Live Reader
A live reader gives you a person to play against, and a good one will adjust to what you are doing in a way no recording can. That is a real advantage and we are not going to argue otherwise. What a live reader cannot do is be available at eleven at night when the tape is due at nine, run the same line twenty times without fatigue, or hold a consistent pace across every take.
Our scene partner reader is built for those cases: it speaks the other character's lines back to you at a pace you set, so you can rehearse and tape whenever the deadline actually lands. If you have a reliable reader available, use them. If you do not, this is the difference between taping and not taping.