I prefer projection mapping over physical lighting of the mountains for a few reasons:
1) It can be made slightly more dynamic and create the illusion that portions are moving slightly, or at least give the illusion of "life".
2) Physical built-in lighting is lovely at night, but an eyesore during the day. Think Cinderella's castle at Christmas. Even with the most clever masking of tiny physical LED lights, the mountains still wouldn't look quite natural during the daytime.
3) It is something that won't be a nightmare to fix when it breaks. We all know AK's track record.
As Tree of Life demonstrates, the tech is "there" to pull this off correctly.