The "Aegis is not a Ward" part is there because upon first looking at the Ward rules, one player immediately wanted to know how they affected an Aegis. That same player is the reason there is "Do not attempt to get cute with Faerie Modifiers" in the Craft/Creation Magic section.
The Creo Creation using Room or Structure does not have to be a ritual, it can be any spell or enchantment. In fact our most common use for it has been in enchanting items. We have ones that create that diffused but comfortable light you mentioned, but also ones that provide a comfortable temperature.
If you want to see more uses of some of the House rules, specifically the Creo Creation and Environmental Trigger special activation, you can look at my characters Lab Thread. It also contains a descriptive write-up of the Covenant since temprobe asked for it (though I did take a month to post that due to having to find time to consolidate and clean it up).