I think that's a legitimate argument but deployments to VMs that are already up and running can also be fast, and for me they are, so it's not overwhelming. My feeling is that one day I'll reach a level of complexity/deployment time where the benefits of containerisation become clear, but I'm not there yet, nor anywhere near it.
Being able to load more containers than VMs onto a server is another piece...
Beyond that, it's not too much different than running VMs was earlier on, it took orchestration and tooling to get working and there were growing pains... much of that abstracted well before becoming popular.
In the end, containers are just another step towards wherever we are going... I think it's pretty nice, but the tooling is just now starting to catch up.