I would assume that lighting technology was never intended to be changed in-game. Kinda similar to how you can’t change the FE, Streaming, and Legacy Physics Override in the same case. I don’t know if this will be intended on full release though.
Also if you’re trying to test the property in-game as of right now, I advise not doing so because only Studio has the property. The client currently does not see the property.
Edit: Seeing that you get the error in the command bar, maybe the property is locked on all levels of scripting access.
What’s your use case for needing to access Lighting.Technology? I can’t see a reason why you’d need to access that property. As well, with what Locard said, it most likely isn’t intended to be manipulated in-game.
One of these days I’d like to make a building game, and I’d want players to have the flexibility of being able to change most of the same stuff they can tweak in studio.
But since I have yet to deliver such a game, it’s not mission critical for me. I’d probably just pick my favorite and make all my users deal.