An essay-only tool is enough when essays are the assessment plan. A literature or composition teacher who grades drafts and final papers and nothing else does not need coverage for exam responses or code, and a narrower tool is easier to learn and to justify on a budget line.
The calculation changes with a mixed timetable. A high school teacher with an English section, a social studies exam, and a computer science elective is running three grading jobs. So is a university department where the writing seminar and the programming course sit in the same budget. At that point the question stops being which tool grades essays best and becomes how many tools the term needs.
EduSageAI answers that by keeping the rubric at the centre. The criteria you write drive the score whether the submission is an argumentative essay, a written exam answer, or a Python assignment, and the review step is identical in each case. For the essay half of that work specifically, the AI essay grader page covers criterion-level scoring in detail, and the rubric grader page covers scoring against criteria you already have.