But when potential employers come looking at your work they'll say "hey this code is shitty! It's not a work of art with 100% code coverage tests and perfect in every way. We can't possibly give you a job. Every line of code in our corporate repo is Mona Lisa quality, we can't let rubbishy developers like you in."
Sure, at small companies where developers interview you, or maybe if you link to a specific relevant project in your cover letter, you might get a pair of eyeballs. But I think people vastly overestimate the readership of their repos when looking for jobs.