At the moment I have a RPi2 doing nothing. What would be the advantage of running Lede on this compared to let's say a "full" raspbian??
Adventage ? I don't think so... What do you want to do? For example, If you want to make your Raspberry Pi as a New Home Firewall. Of course, a Raspberry Pi could be used as a firewall with the default Raspbian distribution with the right configuration, packages, and tweaks. The key value of OpenWRT/LEDE, however, is that it provides an easy to use and manage firewall solution for those who are not linux power users. Most common operations can be done through the friendly web interface.
I couldn't think of any advantage either, but I noticed people are putting it on their RPi2/3. The 3 maybe as travel router with the build-in wifi, but for that I already have an old TPLink (4/32 only, but for simple work good enough)
Thanks, I will think of another purpose for me RPi.
I suspect the PI will perform better as a travel router if you want to use a VPN solution, which IMHO, is the main reason to run one of these.
NAS\Cloud http://www.techradar.com/how-to/computing/how-to-build-your-own-raspberry-pi-nas-1315968 and many others
Home Automation https://home-assistant.io/docs/installation/raspberry-pi-all-in-one/
VOIP\Asterisk - https://www.freepbx.org/