Thesis/support essays convey a central idea clearly and succinctly. Because thesis/support essays open up and expand upon a single main point, they're suited to short reports, position papers, and critical analyses. Because they can, with practice, be written quickly, they're also handy for essay exams and letters of application or recommendation. As you become familiar with them, you'll no doubt see other uses.
The basic thesis/support pattern promotes clear, systematic thinking on a single subject and can therefore be helpful whenever you want to set forth ideas and facts in an efficient, orderly way.
You may notice that the form presented here channels your thinking and writing into a single direction. This channeling effect is both a limitation and a strength of thesis/support essays. It's a limitation because it prevents you from ranging widely over a field of interest, as in an informal essay. The channeling effect is a strength because you won't wander from your subject, and because your main idea will always be supported by well-organized details.
The basic thesis/support pattern promotes clear, systematic thinking on a single subject and can therefore be helpful whenever you want to set forth ideas and facts in an efficient, orderly way.