Minecraft Bedrock and Java Old Snapshot / Update Access

Some Java player can convert their world back to an old update / snapshot to try it out or have some fun. Some rather play in the old versions. If it doesn’t affect Minecraft performance too much, I think these old updates should be able to be applied to any world in the experimental tab or a possible new tab. I don’t see any problems with playing Minecraft pre Nether Update, apart from possible overall game performance and bug errors associated with it. If it’s glitchy, scrap the idea and put it on the bad ideas wall. If not, have it only be able to be applied to new worlds, or creates a copy like all other experimental features.