Space doesn't really change it though because the effective bandwidth between nodes is reduced by the overall size of the network and how much data they need to relay between each other.
We use them because they're many orders of magnitude cheaper and simpler for anywhere near the same bandwidth for the distances required.
That's incorrect. Lasers can suffer from atmospheric interference and fogging on earth.
Here is a post from NASA explaining why they like laser communications better than RF in space.[1]
[1] https://solc.gsfc.nasa.gov/modules/kidszone7/mainMenu_textOn...