Update:
When you first begin to understand the length-tension relationship, you assume that any exercise overloading the muscle away from the midpoint is useless.
Upon closer examination, differing internal moment arms throughout a muscle and sarcomere non-uniformity make it clear that all positions throughout the range of motion have some value, even the most shortened position overloaded through elastic resistance.
Therefore, I apologize for the dogma presented in the past, encouraging you to keep an open mind toward variety in bodybuilding for the best results.
Many assume that popular things must work. This could not be further from the truth. Fitness brings trends and gimmicks all the time. People look to ride the next great wave. They hope for quick and easy results. They ignore sensible, time-proven methods. They fail to buckle down for hard, consistent work. Resistance bands have grown widespread for reasons beyond any real value. They are convenient, portable, and colorful. They have a host of attributes that have nothing to do with tough exercise.
Flaws
The worst flaw comes from the low resistance. Toning does not exist. You grow only stronger or weaker. Any resistance that allows muscle to generate tension can develop strength. Any machine, free weight, etc. can do this. Unfortunately, most resistance bands provide something only slightly better than nothing.
This often allows women to justify a measly effort. This seems not much different than attending some pointless group classes if only for social interaction and approval. Travelers may feel content doing obviously poor exercise. They do endless repetitions and feel almost no fatigue. Convenience matters little if poor results come with it.
Bands seem almost worthless even for athletes as well. The concept of accommodating resistance applies in powerlifting circles. In physiology, this concept is flawed. Resistance bands used by powerlifters aim to overload the lockout portion of any lift. They often apply more resistance here to misguidedly balance the strength curve. This portion of any exercise feels easier due to better leverage, not because the muscles function well here.
They may want the exercise to feel hard throughout the full range of motion, despite this not working best for stimulation. Muscles operate most strongly in the mid-range for any exercise. This occurs since the muscle fibers overlap optimally here. Other positions feel easier only because of better leverage. Emphasizing the endpoints harms effective loading.
Resistance bands stress our muscles further as the range of motion continues. The resistance grows greater as our muscles actually grow weaker. The constant tension they provide actually represents a disadvantage. When using bands alone, you could simply stop at the midpoint in the range of motion. This provides a less clear standard though and attempts to promote resistance bands as actually useful.
Resistance bands often allow exercises that so happen to act less effectively and can feel dangerous anyway. This includes isolation meant to take place unloaded. They make good exercises feel awkward. They may have rare use in rehabilitation.
In some circumstances, an explosive athlete may benefit from learning acceleration to overcome heavy resistance. Resistance bands are unnecessary but may help teach this concept. This advantage would come neurally and not physically, so hardly requires resistance bands.
Avoid Resistance Band Training
Instead, use basic free weight exercises that provide enough resistance. If traveling, go to a gym with some basic equipment. Resistance bands fail to provide ideal progression. You need to increase the resistance if you aim to gain muscle size and strength. Everyone should strive for more strength. This should occur regardless of abilities and goals.
I suggest ignoring resistance band training. Instead, focus your effort on tough but productive strength training.