You could upload someone else's work. Why not?
You might get caught. Think not? Really? You think that software can't detect duplicate work? Hmm.
Also, remember that every exercise you submit is graded by a person. Can you slip all of your cheating past your grader?
You add your initials to every submission; the website won't save your submission until you do. You assert that you did the work. Think that means nothing to people judging your case, if you're caught?
This course will help you learn skills you can sell in the job market. Get you some benjamins.
Maybe you can lie your way into a job, say you have the skills, when you don't. People will figure out you're not skilly, though. Then what?
If you do have the skills, people will see you as the go-to person to get stuff done. That's a good rep to have. This course will help you learn the skills, but only if you do the work.
People judge each other. That's the way humans are.
If someone sees you cheat, what are they going to think about you?
Are they going to want to work with you? Would they be afraid that you would cheat them?
If someone asks about you, what are they going to say? Whether it's for a job, or to ask you out on a date. Would you want a friend going out with someone you know cheats?
This is how you think about yourself.
A common statement is, "I don't cheat, unless I have to." "Have to" covers a wide range for some people. "I have to watch the game with my friends." Really?
Not turning in an exercise won't kill your grade in this course. In fact, there are so many exercises, that missing a half dozen won't wipe you out, either. It will have an effect, of course, but will not be fatal.
You never "have to" cheat in this course.