Heroku request timeout vs Nodejs architecture

At this link (https://blog.heroku.com/timeout-quickly#how-webservers-work), I read:

All webservers will work in a similar way. Any new request will go to a queue, and the server will process them one after the other.

This means if you have 30 requests in your queue, each taking 1 second to be processed, that will take 30 seconds for your server to empty the queue. If one of those requests is a file upload for example and takes 5 minutes to be processed, it means that any other request will be stuck for 5 minutes. That’s 5 minutes during which no one else can visit your app.

This reasoning is used to justify having a 30 second timeout for every request on Heroku-hosted web servers (https://devcenter.heroku.com/articles/error-codes#h12-request-timeout).

However, is the above really true for Node, which is supposed to be async? Is there any real justification for having such a timeout for a Node server running on Heroku?