Teaching in college is one of the many opportunities for professional development that most graduate programs offer. The level of responsibility for graduate teaching assistants can range from assisting faculty members (i.e., grading papers, copying tests, covering lectures while professors are out of town) to being the primary instructor responsible for the course, or even teaching an online course. Teaching in college is a great way to get some valuable teaching experience that will come in handy if you plan on pursuing a career in academia.
Becoming a graduate teaching assistant to distinguished professors in your field can grant you unique opportunities. You will be able to get to know your professors better and possibly to create professional relationships and mentorships that you could eventually use for a letter of recommendation for internships, postdoctoral fellowships, or even faculty positions. In addition to the potential for letters of recommendation, you will also gain powerful knowledge and insight about teaching at the graduate level when you work as a graduate teaching assistant for distinguished professors.
Teaching in college can be rewarding not only to your graduate school career but also to your professional development. Being a graduate teaching assistant in a variety of courses during your time as a graduate student will make your CV stand out when you apply for internships and postdoctoral fellowships. Additionally, graduate teaching positions are often connected to funds and stipends, which help offset some of the costs of living and education.
The new perspective, insight, and experience of teaching in college can all contribute greatly to your professional development. Teaching experience will give you more insight into your field and will give you more expertise that can make you more marketable after you graduate. The more experience you have, the more marketable you will be once you have your degree.