A website is the online hub for your business / brand. It should function as an arm of support that is always "on". It should also speak very clearly to the what, how, why, and who of the business / brand.
I have designed 130+ websites in my career and each is unique to the needs, goals, services, and mission of the business / brand. Designing and developing a website is an extensive way to hone in on the visual representation of your business / brand and how it reaches your audience.