I'm curious now -- are there any other alternatives with similar philosophy/benefits?
Sometimes people find just starting with a messy part of the build process, or starting to replace dockerfiles here and there can add value, without having to change the world.
Some of the short-list of differences: we use YAML for our configuration language, Dagger can use full-fat languages to define its pipelines. Our feature scope is broader: you can use us to vend IDP-like stacks to your developers if you're a Platform Team; we make development with remote Kubernetes clusters very easy, including all the remote image builds; and we have a number of integrations so you can bring your IaC tool of choice (Pulumi, Terraform) into your pipeline and set up service -> infra dependencies.