In Chai assertion library what is the use of "assert.equal()" when we already have "assert.deepEqual()" and "assert.strictEqual()"?

In Chai assertion library what is the use of "assert.equal()" when we already have "assert.deepEqual()" and "assert.strictEqual()" for both strict and deep equality assertions? Also it is mentioned that "assert.equal()" uses non-strict equality. What is the difference between non-strict and deep equality? Why can't we just use "deepEqual" instead of "equal"?