All three courses cover linear algebra. Math 2220 focuses more on computational techniques and applications, while 2250 and 2260 emphasize mathematical proofs and a more conceptual approach.
Math 2250 (linear algebra) or 2260 (intensive linear algebra) is recommended for students who wish to take further proof-based mathematics courses. Students majoring in mathematics, Math + CPSC or Math + Econ are required to complete either Math 2250 or Math 2260.
In more detail: For math majors, and students who wish or need to continue with proof-based math courses, the theory and proof writing skills learned in Math 2250 or 2260 provide essential preparation for further study. That is why the math major does not accept Math 2220.
Outside of the major: generally speaking, proofs are useful in many fields. They help one to become a better problem solver, evaluate different approaches to a question, consider options along the way, keep track of important details, check solutions for correctness, and present them in a way that is accessible to others. These skills are very helpful, in math and outside of it.
For that reason, many students find it beneficial to take Math 2250 or 2260, even if they do not continue with further math courses. If you try the course and enjoy it, the skills you learn will not be wasted.
If you enjoy applications more, and want to get lots of practice solving concrete problems, rather then focus on theory, then Math 2220 is a better choice. It provides great preparation on the practical side of linear algebra, and it is preferred by the majority of students in engineering, social sciences, and many other fields.
Moving from Math 2260 to Math 2250 is permitted until Midterm. Moving from Math 2260 or 2250 to Math 222 is permitted until the end of the third week of classes (this has an earlier deadline because the courses are quite different, and it is too difficult to catch up later on). You can read more about how moving works in our Calculus FAQ.