EC2 root volume expansion for CentOS7

My EC2 is running with CentOS 7 HVM community image which comes default as xfs file system, and I had a root volume with 10GB which I extended to 15GB after detaching > creating snap > reattaching to /dev/sda1 but I noticed that I did not had to run any kind of resize command just like with ext file system we have to run resize2fs and partition now shows 15GB without doing anything. While there is a command xfs_growfs but even that I did not run.

So, is this normal behavior of how xfs is expanded in EC2 world(and others), or something else?

Regards, Farmi