Distrobox is such a cool utility! Tried it out today and don't see myself switching distros now for a long time :)

What is distrobox?

It's essentially running a linux container on top of your own system. Which means you can use the toolkit of those distros ( for example the package manager of that system) to install apps from their repos, even gui apps. But those containers also has access to your original filesystem so be careful how you use them. Might want to watch Brodie's video on it.

(Famous last words of a distrohopper)

I Wish I would have discovered it before. I think it's very useful when you want to install proprietary software like Matlab or Vivado. With distrobox you avoid to bloat your system and when you want to remove them you simply remove the container

100%
To add to this, you can even specify a home folder for the distrobox so it doesn't even clutter your home folder. Really neat

It genuinely is. I really like the combination with an immutable OS like OpenSUSE Aeon because you have a super stable base that you can add whatever packages you need to via distrobox.

Thank you for sharing this! It was just the thing I needed to get a project setup. Toolbox couldn't pull the version of Fedora I needed to use for whatever reason, but Distrobox works great and has a much wider selection of distributions.

Why would you need multiple distros at the same time?

Think of it as multiple user lands on one distro. So, why?

What if I really love the stability and familiarity of Debian Stable but applications that are either ancient versions or totally missing in Debian? Well, I could use Distrobox on Debian to get access to the Arch Linux repositories ( the largest collection of Linux software anywhere ).

What if I do not want to install huge Flatpaks for the above and prefer more traditional package management and more timely updates?

What if I want to setup a dev or test environment, want to be able to make a mess and remove it later, not also want access to my other tools and files from that environment?

What if i want to experience other package managers and userlands without having to lose my existing system only to discover I do not like it?

What if I want to build software for a specific disto and want to access files and tools on my main distribution to do so?

I am sure there are many, many more reasons.

Anyway, it is just one way to do things with pros and cons like anything else. Personally, I really like it.
One use case I had was I wanted to use STM32 Cube IDE, but it has a dependency on python 2.7 I think it was. I had some trouble installing it on my main OS, but I was able to get it to work on Ubuntu 22.04 running in a Distrobox.

i couldn't figure out where the binaries for their systems are kept and that's really the one thing keeping me from having a great time with distrobox

Brodie had a video on it, might want to check it out.
- Here is an alternative Piped link(s): https://piped.video/watch?v=FhW-3PPldAg
  
  Piped is a privacy-respecting open-source alternative frontend to YouTube.
  
  I'm open-source, check me out at GitHub.

How does Distrobox compare to VanillaOS?

I use Distrobox with my NixOS machine for when I need AppImage support (or some random binary that isn't equipped for Nix's weird ass directory layout) and it's amazing! Pretty much native speed, and when I'm done with it I can just wipe it out. Perfect!

Distrobox is great and I also used on Fedora Silverblue before switching to NixOS (with similar use cases).

For running AppImages there's also appimage-run on NixOS. https://nixos.wiki/wiki/Appimage
- I'm aware, but the appimage I run (Slippi Launcher) will run other appimages, and appimage-run can't handle that, since it extracts the appimage, then runs the contents, but it won't automatically do that for other appimages that are run.
  
  Which is why I used a Distrobox and it was awesome, worked like a charm. I used Arch previously, and I just made an Arch distrobox and it worked perfectly.

Is this gnome?

looks like it yeah - i had a similar setup a while back.

I read their GitHub page, but I still don't understand what this is really. What does it do and what is the point?

Similar WSL2. But this is for Linux

What is the frequency indicator on the right side of your system panel?

Properly just Process Manager with the icon from macOS Activity Monitor.