Any project will benefit from scenario planning and creating personas, they make it easier to focus on your customers by being reminded of who they are.
The outcome will represent goals, motivations and behaviours of your customers and put simply personas help to put a human face to a strategy and imporve their experience of your brand and ultimately help them on their journey through your website.
By defining exactly who your products and services are designed for personas will help build focus within your team.
As an ongoing development personas promote dialogue about who your team are working for. For example would Jane find this useful? Would John be able to find his way around this interface?
If you're considering new features or a website redesign the benefits of defining personas before committing to a budget will deliver a strong customer focus.
Looking further ahead if you wanted to evaluate a design – your personas will help or recruit users for testing – personas will help.