Your dissertation is a significant piece of writing that will be read by scholars in your field. In addition, dissertations are archived and made available to the public, so your bibliography provides a way for readers to find the sources you used.
Dissertations are also used as sources themselves. When another scholar wants to build on your work or challenge your arguments, they will need to consult your bibliography to see what sources you used. By including a comprehensive and accurate bibliography, you make it easier for other scholars to engage with your work.
Including a bibliography is also a way of demonstrating the rigor of your research process. By showing that you consulted a variety of different sources in developing your dissertation, you demonstrate that you have engaged in a thorough and thoughtful research process. This can give your work more credibility and impact within the academy.
Ultimately, whether or not to include a bibliography in your dissertation is up to you and your advisor. However, if you are unsure, it is generally better to err on the side of inclusion since omitting a bibliography could make it harder for others engage with your work down the line.