It is important to uphold academic integrity in your coursework because if you cheat, you will not learn.  Besides getting grades and earning diplomas and degrees, the purpose of school is to learn.  If you copy from someone or otherwise cheat, you do not learn.  If you let someone copy off of you, that person will not learn.  You are not really helping anyone in the long run when you cheat for them.  All you do is risk getting you both caught.  You can also face serious consequences, including possible expulsion from school.