I have a tiny application. Yet it involves 5 containers. Some of the applications are a pain to install unless you go with a specific linux distribution and use their existing package. I don't have the time to manage all that crap through a labor intensive method or manage 5 separate servers when I can do it on one with containers. When I have to do things quick and dirty I just use a shell script with docker run and that's fine for 90% of projects because they don't pan out anyway. I can trivially switch to docker compose and then if I need scaling go to Kubernetes. It's a 100% solution. For the smallest prototype to large scale solutions. If you manage your servers manually you will either have to learn ansible which is just plain awful and difficult to use or you spend a lot of time doing everything yourself. Both cost time at the start of a project and many people don't have that time to waste on useless purism.