The loading state helps users see the form is in the process of being submitted. According to the first of Jakob Nielsen's 10 Heuristics, visibility of system status is crucial — the system should always keep users informed about what is happening right now and provide clear and on-time feedback. This makes users feel in control of the system, so they know how to act to reach their goal. Showing the button's state also increases user trust in the brand.^[1]