I’m running a 3 pi cluster with k3s at the moment. The main benefit I’ve found is that all my pis run exactly the same software setup as a base so it’s easy to add new ones or replace/update one. I use a deployment management application to push my deployments too which means it’s super easy to redeploy everything if something goes funky.
You can even compile to a native executable these days I believe so you don’t have to have the .net runtime installed or bundled.