Some people love Composer. 

They use it to build their PHP projects and manage all the external libraries and dependencies. They love it so much they say things like this: "Composer should be the only way to build a Drupal code base."

That approach is misguided, and I'm going to give you 5 reasons why.

Composer is a great tool, but it's far more limited than some people realize.

I'm going to mostly write about Drupal in this blog post, because it is further down the Composer path than any other CMS. But, some platforms like Magento and Typo3 are headed that way too.