Having been in a similar situation to you, I say go for it. Arch taught me the basics about Linux that I think everyone should know to understand what Nix does under the hood, but as soon as I saw how well NixOS worked on my secondary machine I switched my primary over and I'm not regretting it in the slightest.
That's not to say Arch is a bad distro, in fact I'd say 99% of my Linux knowledge comes from that excellent community, it really is KISS, but it makes no secret out of what this actually means: making it simple for the maintainer by delivering an almost untouched upstream, which I agree brings the ecosystem forward as it pushes toward a bazaar model where everything works together without the distributor doing too much work of their own. But if you want to keep a system clean in the long run, at one point you realize that you need a system like Ansible (which for me retrospectively has shortcomings that can only be fixed in the underlying system) or Nix integrated in your base system, which NixOS does.