Do what feels right for you!
Personal trainer handbooks recommend working out for 5 days a week because the risk of working out an additional two days outweights the benefit (injuries, overtraining).
Some studies only wants one to work out four days a week, two days of heavy lifting and two days of cardio for maximum muscle growth (this is when you actually lift to failure, which usually does not happen with videos).
The body needs time to recover from workout stress. Without recovery, your body cannot get stronger and/or improve on cardiovascular endurance. Of course one can workout daily for a long period of time but eventually your immune system will be compromised and you are more prone to get colds and injuries.
Think of a rest day as a day necessary for your body to get stronger - not as a lazy, unproductive day.