Performing ''the biggest bang for your buck'' compound exercises will help you reach your goal MUCH faster and more effectively than if you stick to machines or perform isolation exercises. This goes for people who are trying to lose body fat, add muscle, improve their overall fitness, it serves ALL of these needs.
While I do like to throw in activation exercises, more so in the beginning stages, the majority of the exercises should be compound in nature, and not on machines.
Most exercises are able to be modified to meet your current fitness level. For instance, you can't perform barbell squats? So what, do bodyweight squats. Still can't do those, perform body weight box squats (basically learning how to sit down and stand up) and increase the difficulty as your strength and/or mobility improve.
Rome wasn't built in a day. However, if you want it to be built in this lifetime, perform compound exercises and aim to do most if not all of them without machines, AND strive to be uncomfortable!!