From the isolation standpoint, yes. However, containers were invented to slice large servers into tens or hundreds of smaller machines, so it's kinda given that there is more than one container per server.
From the ops standpoint, it's even trickier - there is a lot of tools and services on the market to run, monitor, and debug containers. Docker (OCI) containers is the de facto standard runtime and packaging format, so it's much easier to operate them. Today, you can even exec into distroless containers with `kubectl debug` (or my own `cdebug` tool). In contrast, from my standpoint, unikernels look like black boxes that you launch and prey they behave well. The unikernel ecosystem needs to mature a little bit more before I'd consider it as a container alternative.
There are, of course, situations when I'd go with a unikernel-packaged app even today. For instance, if I needed a scalable to zero but still very low latency app and I wouldn't be concerned that it might not work well with a trimmed-down kernel, I might consider deploying it as a unikernel. In other words, the upsides of this solution should outweigh the (sizeable) downsides of using a non-mainstream tech.