I'm not suggesting that anyone would use the ELL to connect to Richmond, but London Overground is about providing an orbital network outside Central London with the various connections that can be made along those stations.

I sometimes commute to Essex Road which is on the FCC Moorgate line and would rather travel on one train to Highbury and Islington, than travel to LB, then tube and train it.

Incidentally there are other advantages after Monday, the 4 trains to CP will enable you to change for additional trains to Victoria.

There will be two trains per hour from NJ to Gatwick (as now), however there will be a more regular service to East Croydon, which means the 4 ELL trains to West Croydon will be useful to interchange with Southern services.

NJ will also have 6tph fast to London Bridge.