2015 was the year that Apple moved to NVMe SSDs, so they are bound to feel much more snappy than spinning rust disks, regardless of the file system involved.
https://www.anandtech.com/show/9136/the-2015-macbook-review/...
https://www.anandtech.com/show/9136/the-2015-macbook-review/...
They are going to need to support and perform well on non-SSD systems for quite a while.