For me the config management aspect of home-manager is mostly useless. It takes a lot more work to set it up, looks far uglier, and you need to maintain it because parameters change over time. Saving dotfiles in a repo, and symlinking them on install is simply easier.
The only two scenarios where it's actually useful is when you have slightly different configs for different devices, and when the program doesn't support dotfiles. A pretty cool example I've seen for the second one is managing Firefox customisations (settings, plugins, additional CSS), but I'm only disabling horizontal tabs so it's not worth it for me.
It's pretty fast, especially if you don't get into flakes right away. You basically just install nix with a one liner -> install home-manager through nix -> start adding packages to list.
Here's a comment I made when I was starting out with basic instructions. Do note I'm now using this command for updates instead (updates hm, package definitions, and the packages themselves)
cd ~/dotfiles/nix/ && nix flake update && nix-channel --update && home-manager switch --flake ~/dotfiles/nix/