Once you start the video chat, there are 2 ways other folks can connect to your "party-room" (it isn't really called a party room, it just feels a lot more fun that way), the instructions are on the right-most column: either visit the URL that you created, or scan the QR code.
In the image above, I've connected to the same room using 3 devices. My laptop's browser, my iPhone's browser, and my iPad's browser. No download, no sign up, and no payments necessary-- just a browser and some Internet access.
You'll notice a small white box in the bottom corner of participant 2 and 3. These are "verification" codes, used to ensure that every member is connected in a secure manner.
There are a number of "other" options too (bottom left corner), that include choosing your audio/video source, blurring your background (or adding an image, like in a Zoom call), as well as enabling/disabling your audio/video.
I think this is a very very useful tool that's available to you regardless of your budget, application usage, or device ownership. You just need a browser with some Internet.
Note: so far the only "privacy" issue I can think of is if your room name is too easy to guess. My room was called "Prithvi!"; if you name your room "test", you can't assume no one else will join it. Be smart when naming your party rooms.