I am not sure if this would necessarily be considered a bug and rather "intended" behavior as you are directly deleting a folder Minecraft is expecting, but just in case:

Deleting the temporary datapack folder at world creation gives an error:

Failed to initialize pack directory C:\Users\<user>\AppData\Local\Temp\mcworld-<numbers> monitoring
java.nio.file.NoSuchFileException: C:\Users\<user>\AppData\Local\Temp\mcworld-<numbers>
	at java.base/sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:85)
	at java.base/sun.nio.fs.WindowsException.asIOException(WindowsException.java:112)
	at java.base/sun.nio.fs.WindowsWatchService$Poller.implRegister(WindowsWatchService.java:366)
	at java.base/sun.nio.fs.AbstractPoller.processRequests(AbstractPoller.java:266)
	at java.base/sun.nio.fs.WindowsWatchService$Poller.run(WindowsWatchService.java:596)
	at java.base/java.lang.Thread.run(Thread.java:833)

To reproduce:

1. Click Create New World
2. Click Data Packs
3. Click Open Pack Folder
4. Delete the temporary datapack folder that opens
5. Go back to game and click Done, and then Data Packs

The error described above is logged.
Instead of clicking Data Packs again at step 5, you can also cancel back to the world selection screen, and the error

Failed to list temporary dir C:\Users\<user>\AppData\Local\Temp\mcworld-<numbers>

is logged.

Additionally, attempting to create a world after the temporary directory is deleted gives error

Failed to copy datapacks to world <world name>

with a "Failed to copy packs" error in-game alert showing.

The world folders for these are still created, but the only thing inside of them are session.lock files with a snowman emoji inside them.