It’s certainly worth trying to see if it works with the devices you are already using. 
CoRE is a new rules engine which is still in the early design phase. So there may be glitches, and you may have to uninstall and reinstall in the future as changes are made. It’s also very sophisticated, with a complex setup. So if you just want to solve this particular use case, you might try a simpler smartapp for now. If you want to get in on and influence the development of what I’m sure will be a major new smartapp, look into CoRE.
If you’d like to look at some of the simpler but more mature lighting smartapps, choose the Lighting link on the quick browse page:
http://thingsthataresmart.wiki/index.php?title=How_to_Quick_Browse_the_Community_Created_Smartapps
Another Option: a Smart Nighlight with 8 color notifications
BTW, for a different approach, Homeseer has a zwave nightlight that has its own motion sensor and can change to one of 8 colors, including pink and purple, which is fun for a child’s room and lets you give multiple notifications. You can also pretty it up by putting daisy petals around the central light.
A number of community members have used it. It’s on pre-order right now because they’re getting ready to release a zwave plus version, but it might be worth waiting for.
http://store.homeseer.com/store/HomeSeer-HSM200-Z-Wave-Multi-Sensor-P1882.aspx
