There is no right or wrong answer to this question, as it depends on the individual website and its needs. However, it can be argued that a website should have a blog if it wants to be seen as an important and credible source of information.
A blog can help to promote the website and give it more visibility among potential customers. Additionally, a blog can provide valuable content that can be used to build relationships with potential customers and partners.
Ultimately, whether or not a website should have a blog is up to the individual site owner. However, if a website does decide to add a blog, it is important to make sure that it is well-written and provides valuable information for visitors.