depends on the person(s) or company creating the site, for larger companies, there'll be various people who would have a say on how the site works or flows, eg

depends on the person(s) or company creating the site, for larger companies, there'll be various people who would have a say on how the site works or flows, eg marketing people, UX, graphic designers, architects, product owners etc... Not just developers each these people may have a different viewpoint on what they want to happen and why