Immutable are the ultimate tinkerer's distros. It's just a different way of tinkering. True tinkering in immutable means creating your own image from the base image and that allows you to add or remove packages, change configs, services, etc.
Example: you create your own image. You decide you want to try something, but you're being cautious. So you create a new image based on your first with your changes. You try it out and you don't like it or it doesn't work for some reason, you can just revert back to you other image.
Another thing worth mentioning, with these distros, you can switch between images at will. I'm new to Linux as my daily driver desktop OS, and I've rebased three times. It's really cool to be able to do that.