Yes, BUT... it doesn't allow the user to switch between multiple different browser configurations AFAIK. I mean, I run multiple instances of Firefox Portable (from PortableApps.com) such a way that each browser instance is in its own separate copy of the FirefoxPortable folder. So the content in each of these copied folders can be configured individually as needed, thereby allowing each modified copy of the same portable browser to be run simultaneously (also as needed).
This is still something that is possible only by using the AllowMultipleInstances=true setting in a file FirefoxPortable.ini in the FirefoxPortable folder AFAIK. It isn't possible to achieve with any other browser (also AFAIK). Even the non-portable edition of Firefox doesn't let me.
I run multiple individually configured instances of it in multiple individually configured Sandboxie-Plus sandboxes simultaneously. This strategy doesn't prevent me from using Multi-Account Containers and Firefox profiles. Think of it as a separate layer that can be used on top of all the other options.
Sandboxie-Plus doesn't use virtualization. It means that you can install Windows in one or multiple VMs, then install Sandboxie-Plus on each, and use it to create one or multiple sandboxes on each. It also means that you don't necessarily always need to run a VM.
It matters because installing Windows 11 in a VM that runs on another, separate installation of Windows 11 eats more RAM when RAM can be put to better use to let apps run faster and to fill up a ramdisk, for example. This gets exacerbated with multiple VMs running simultaneously. Running a browser under the supervision of Sandboxie-Plus (former Sandboxie) is, and always has been, among the most common of its use case scenarios so, it makes perfect sense to embroider on it for this purpose.
Also, Sandboxie-Plus goes several steps beyond the "traditional" concept of containerization. It has an advanced featureset that makes it unique, which it does in various many ways. The option to point the sandbox location to another folder on a separate drive (such as a ramdisk) as needed is only one example of this.
