Only some banks allowed ITR but most of them its payslip and need net salary.
Think of like this.. Credit card are meant to settle "monthly", so they need to check your capability based on "net salary of that month". Annual ITR may not helpful to provide sufficient limit because you can't settle "yearly once with bonus" but only monthly salary.
As said, still some banks allowed ITR take advantage and some dont. It depends on which bank you're going to apply.