Help understanding Docker for Raspbian

Hi all, I’m trying to install Docker on a Raspberry PI 3 B. I followed the general steps here:
and by the time I run the Hello World container, I read that to install Docker Engine in Raspbian you must use the convenience script.
The thing is, even if I skip the Set Repository step, after running these commands:

sudo apt-get install docker-ce docker-ce-cli sudo docker run hello-world

The hello world run fine.

I already uninstall it and I’m going to install it using the convenience script but I wonder: what’s the problem with installing it using the normal way? Since I only run a Hello world container, I want to know what’s the explanation about installing it the normal way in Raspbian without setting the repositories. I also want to know why the convenience script works. What’s the difference?

Thank you in advance.