Compound Exercises vs. Isolation Exercises
Compound exercises are exercises that use more than one joint and more than one muscle group at a time. Generally, it is better to do more compound exercises in a workout that isolation exercises. This will stimulate all of the major muscle groups, giving you a bigger bang for your buck, or in this case, more muscle recruitment in a shorter period of time. Compound exercises also help develop the body proportionately as where if you focus on isolating a muscle group, such as biceps, they will grow proportionately to you calves.
Isolation exercises do have their benefits though. As you become more experienced of a lifter, you will notice genetics may not be on your side in certain areas of your body. This is when isolation exercises come in. They are great for giving extra attention to those trouble spots, or areas that you'd like to focus more on.
So even though compound exercises are much more beneficial when it comes to exercise, there is nothing wrong with adding in some isolation exercises as well. Just remember, it is generally best to do your compound exercises prior to isolation exercises so you have maximum muscle recruitment and energy stores to complete those complex multi muscle movements.