When you have something simple to learn, or you're just getting started in a topic, taking a behaviorist approach helps you to gain fundamental, cut-and-dry knowledge. Behaviorists rely on what they can see, so behaviorist techniques involve visible stimuli and responses. You've heard of Pavlov's dogs, no doubt - one of the classical behaviorist examples, where dogs were conditioned to salivate at the sound of a bell after Pavlov associated food (something that naturally makes dogs salivate) to the bell. People can be conditioned in similar ways - John Watson conditioned a child to have a fear response to an animal the child did not previously fear, by making loud noises whenever the child approached the animal (McLeod, 2014).
Behaviorist approaches help lay a foundation for learning, because you can easily tell if a learner is picking up on fundamental concepts by observing when they've picked up on something enough to pass a simple test, like a quiz or matching exercise. As long as you can reduce a concept or topic into small enough pieces to measure when a learner is catching on, incorporating behaviorist techniques work. Positive reinforcement (like badges or high quiz scores) or negative reinforcement (like shame or punishment) help learners know when they are on the right track.
Perhaps you remember a parent saying to you, "if you stop crying, I'll let you watch cartoons," or something similar. The parent is looking for the outward action to cease, and offering a reward in return. If you, as a child, found the potential reward satisfying, that would induce you to perform as your parent was directing you, according to Skinner's principles of operant conditioning (Virgina Tech Faculty, n.d.).
Once you start looking to have a child develop a larger sense of ethics and self, or have anyone synthesize smaller concepts into larger ones, make connections across topics, and have learners develop new thought processes and ideas, behaviorist approaches start to lose their luster (Berkeley Graduate Division, n.d.). Therefore, intangible qualities like creativity or thoroughness are difficult to capture via behaviorist methods because they are not objectively observable, and cannot be easily broken down into small tasks or ideas to be easily and quantifiably measured for success. Hence, behaviorist approaches can help build a foundation, but not take a learner to more and more progressive levels of understanding.
When I took German in middle school, our teacher took a variety of behaviorist tacks to help us build a foundation for further learning down the road. Our worksheets contained many exercises on basic translations of single words, as well as simple grammar exercises to help us internalize German grammar and its differences from English grammar. Additionally, we took quizzes and exams throughout the class, giving our teacher many chances to help us make corrections to our baseline knowledge of vocabulary and grammar. Getting more answers correct on worksheets and assessments meant higher grades.
The positive and negative reinforcement of high and low scores on the above, respectively, helped us to recognize and repeat accurate vocabulary and basic phrasing (and to correct incorrect knowledge). "Perfect practice makes perfect", as they say.
Our teacher also used negative reinforcement for behavior concerns. Most syllabi I recall from my youth listed varying degrees of consequences for tardiness, missing class (excused and unexcused), late assignments, and poor citizenship. Whenever someone reached one of the predefined thresholds for consequences related to a behavior, our teacher enacted the consequence as a reminder to the student in question to correct his/her behavior, but also to the rest of us that negative behaviors carry negative consequences (which starts to lean into social cognitivism!).
Berkeley Graduate Division. (n.d.). Behaviorism. Teaching Guide for GSIs at Berkeley. Retrieved from http://gsi.berkeley.edu/gsi-guide-contents/learning-theory-research/behaviorism/
McLeod, S. A. (2014). Classical conditioning. Retrieved from www.simplypsychology.org/classical-conditioning.html
Virginia Tech Faculty (n.d.). Radical Behaviorism. Theoretical Foundations of TEL at Virginia Tech. Retrieved from https://www.itma.vt.edu/courses/tel/lesson_2.html