Let's imagine there is no web application to create the site collection, and you will create the site collection directly without creating a web application,
In this case, Every site collection will require an Application Pool to be created !!
So what's the issue, What's this mean?
This means
- You will be restricted to create
maximum 10 Website Applicationscollection per the web server
based on its hardware capabilities. - A single highly active application pool can utilize 10 GB or more, so More application pools will lead to a Performance Issue.
Now, What do you think?
Do you need to create
250000 site collection per one web application
with the current SharePoint Structure and architecture?
Or you need to be limited to the memory allocation of your web server that allows to you to create 10 site collection based on hardware capabilities at the same time you will face a Performance issue!!
See also