I don’t agree with the a wrong idea part. Docker is, in the first place, a tool. And if a tool fits nicely the task I have to solve, then it’s also correct to use it. I agree, that’s not a mainstream, but for example containers from accetto (and others) help me daily by the following (far from a complete list):
Safe browsing on Internet. If I do research, I don’t know what kind of websites I’ll visit. I also care about privacy and I don’t like wellknown companies to track me. With Docker I can create light weight containers in seconds and then destroy them. The only limitation is missing sound support, but I don’t need it for this kind of work anyhow.
Evaluation of tools. I don’t want to install every unknown tool I want to evaluate on my workstation. Docker containers offer a nice isolated environment and I can keep my workstation lean and healthy much longer.
Proof-of-concept and testing. I can test any new ideas very quickly and. No need to re-configure my working environment each time force and back.
Pre-installed and pre-configured tools. I have a growing set of containers that I use as tools from my main environment. Not to mention, that I can use Linux tools on my Windows workstation.
Replacing VirtualBox. Docker allowed me to get rid of VirtualBox, which I’ve used for years. I love the tool, but I dont’t really need it currently.
It’s true, that Docker’s main usage is not as a virtual machine, but as a service. However, if the former usage so nicely solves so many daily tasks, it would be a real shame not to use it that way.
Otherwise I agree with @tekki, that incorrect usage and incorrect understanding cause problems. It’s just a classic question of right tool for the right task and no tool fits everything.
This isn’t the case by using Docker containers as a virtual machine. The image sizes in the Docker’s listing are not real sizes, because many layers are shared. The real footprint on the hard drive is usually much smaller.
Otherwise I agree with @meyay, that there are important differences between Docker containers and “real” virtual machines like, for example, VirtualBox. It’s important to know them and to use the tools correctly.