My preference for free weights is not that they build muscle faster but that they are less likely to create muscle imbalances via isolation. The body is tuned to work together, not be built one muscle group at a time. Machines are easier to use without learning good technique, but if you have good technique I truly do not find them much safer. It’s marginal, and I think they contribute to injuries of mobility and imbalance in the long run.

All that said, feel free to use them if it’s your preference. These are just my reasons for preferring body weight or free weight. Machines remove the use of many muscle groups that are normally involved in an exercise, especially one’s core.

I think that if you use good technique, free weight is better in the long run. It doesn’t have to be a barbell like this example. You could use dumbbells and still not need a spotter.