Everyone knows the value of homework as practice outside of class, but what is the value of homework to you, as a teacher/trainer in the class? Truth is, many teachers/trainers out there miss out on homework as a valuable in-class tool.
BTW, reason I keep saying teachers/trainers is because of the nature of what ESL "teachers" are doing. We are not just teaching them English, we are supposed to be training them in the use of English. For example: I can teach you how to lift weights, or I can train you how to lift weights - trust me, the difference would become immediately obvious.
So, homework can be used as a training tool in class, but only if it is done at home first. I work with adults doing corporate training in multinational companies. They are very motivated to learn, but have families and work that really puts a heavy tax on their time. Homework? That's a remnant from school days and now that they are all grown up, they just never could find the time to do it.
Until . . . .
I started taking 5 - 10 minutes after every lesson to talk with one trainee. I would go over the dialogs with them to correct their pronunciation, ask them if they had any questions about the lesson (never had anyone who didn't have at least one question even though they had no questions during the lesson), and then I would review the homework given that day for the next lesson.
I would explain the homework in greater detail, making sure they understood exactly what was expected. I then coached them on how they might present the homework, asked them what steps they planned to take to finish it and be ready, and generally helped them do as much of it as I could right then and there. I then told them, "Be ready, because you're going to present your homework at the next lesson." Basically, I was teaching/training them to do the homework.
The results have been dramatic. Homework completion rates began to climb among the class, participation excelled, and more and more time was spent doing the homework review giving them exactly what hey wanted in the first place "More In-Class Practice". By teaching them, patiently one-by-one, how to do the homework, and placing the expectation personally on their shoulders that they be prepared to do it, they would take the time, be more prepared, and do better. English skills have also improved dramatically, and I'm getting better overall results. Isn't that what we're after here anyway?
Now, in a two hour corporate training lesson, the first 30 - 45 minutes is homework review as they are now excited about getting the chance to speak more in class, and less time is spent reviewing the "boring sections" of class. I'm in front of the class less, which means they are speaking more. The more they speak (training) the less I speak (teaching) and any time you are doing more training than teaching, you are going to have far greater participation, higher energy levels in the class overall, and a greater retention level of learning.
It is a common mis perception among ESL teachers that they have to be doing most of the speaking. In fact, the more animated and interested the class becomes, the more talking the ESL teacher does. Why?

Let the class go!! You very well may be the most interesting speaker on the planet, but if your mouth is moving, theirs isn't, and they aren't being trained anymore. Being trained is so much more fun than being taught. Chew on that a while. (Think "sports" versus "history" classes.)
Everyone wins! BTW, as I own my own business now, and I depend on getting results to stay in business and renew contracts. I do not have a school contract to support me whether I am successful or not, so I am motivated to find what really works, and THIS REALLY WORKS! I can easily see how it would make a difference in the regular school classroom setting as well. You just have to teach/train them to do the homework one by one, let them know you expect them to do it the next lesson, and they WILL do it. If you help them succeed, they will accept success.
As a footnote, the ones I first worked with to do the homework did start to fall off after a couple of weeks, so it became important to make sure they knew I expected them to present their homework again as well. Taking 5 - 10 minutes AFTER class, on your own time, to work with them one on one will endear them to you, show you really care, and they will respond to this. They want to succeed because they see you really do care about their success. It is highly motivating, and more rewarding than just killing time.