To what degree is Minecraft RTX compatible with regular Minecraft?

The Minecraft RTX FAQ page states you can import worlds into this beta version of Minecraft: Bedrock Edition, but they highly recommend making backups of them first, since this is a beta after all. It also seems like any world brought into the beta cannot be played on any other version of the game:

Please note that any world you open while on the RTX beta will not be available to be opened in other Minecraft betas OR the non-beta version of the game. We strongly recommend you make a copy of any world you wish to play in the RTX beta and use the copy of the world instead.

To import worlds:

1. From the Minecraft start screen, click “PLAY"
2. Click the arrow icon next to the "Create New" button on the Worlds screen
3. Find the .mcworld file and select it to import.

You can also open .mcworld files just by double-clicking on them - this will automatically open Minecraft and load the world.

To export worlds:

1. From the Minecraft start screen, click “PLAY”
2. In the Worlds screen, scroll to find the world you wish to export.
3. Click on the pencil icon > next to the world you want to export.
4. In the Edit screen, click on the "Game" button located under the words "Edit Settings"
5. Scroll down through the options on the right side of the menu, and then click “Export World” at the bottom of the list
6. Save the world to your location of choice. The exported .mcworld file can be placed anywhere (network drive, USB, etc.) to provide maximum flexibility.