why is mobile debugging better than using normal chrome debugging on your desktop

hello there i am currently working on a website, so i ran it on google insight to test and the result wasn't that good, so i went to udacity, i found a free course for improving website performance and they used mobile debugging they also said that most developers use it, but my question is why to use mobile debugging when i can just right click-> audit -> and find the same dev tools on my desktop chrome, what is the difference ?