This is a studio where you can post projects that take advantage of the Micro:Bit. The Micro:Bit is a low-cost hardware device. Similar to the Raspberry Pi, it is intended to be used to educate children in programming. The ST probably added the extension for schools to use their Micro:Bit with Scratch, but there isn't anything stopping you from using the device for making silly games and interactive projects!
You can add projects at will. Just make sure they actually use the Micro:Bit. Unfortunately, Micro:Bits are chaotic to set up. First you download a hacked Micro:Bit code file. Then, you get Scratch Link off of your platform's repository (app store). Then you go through a long-winded connection process. Then you can use your Micro:Bit with the project! If only you didn't have to reconnect it after every project.
When you eventually connect your Micro:Bit you get a rewarding experience where you can use it as a controller or whatnot.
IF YOU ADD ANY PROJECTS THAT DO NOT USE THE MICRO:BIT EXTENSION AND MAKE USE OF IT, I WILL REMOVE THEM!