Question about formality of PhD motivation letters

Hi everyone!

I am new here and I have been going through the site to look at samples and tips for writing motivation letters for PhDs. However, I have found that most of them start something like "I am writing to apply for the position of blah blah blah...." I was just wondering if there is a reason for this.

Letter for PhD program

Driven by my aspiration to help others, I wanted to be a healthcare professional which translated to becoming a doctor or a nurse for a high school student. I started my university career as a Life Sciences major, but I soon realized my affinity for chemistry and passion for problem solving. After talking to a career counselor, I decided to transfer to the Faculty of Applied Science where I pursued a dual degree in Engineering Chemistry and Global Development Studies. Never losing sight of my goal to help others. I dabbled in biomaterials and biomedical engineering research. While I greatly enjoyed the challenge of learning new skills and applying research data to solve complex problems, I was underwhelmed by the slow-pace and niche nature of physical science research. Not giving up on my dream of working in healthcare,I furthered my education by completing a Masters of XXX to explore another form of research. It was very exciting to explore the subjects of applied physics and mathematics in healthcare technologies in the coursework, but I was most surprised by my unparalleled interest in my graduate research in the field of population health and policy design. The application of the tangible results pushed the status quo of healthcare and I felt a satisfaction I have never felt before. With a passion for improving healthcare service delivery, patient safety and clinical outcomes and a strong enthusiasm for data analytics, I am thrilled to apply for XXX.