This doesn’t meaningfully reduce e-Waste. The average iPhone user is conditioned to trade in their phone with already decent recycling programs being their destination.
IMO, the main (only?) reduction of e-waste comes from reselling the old phones on the secondary market. Re-use is much more effective than recycling. Until the bitter end.
That's a second life, and a valid thing - but I'm specifically talking about people wanting to use (e.g) an iPhone 6S (which will be discontinued soon).
Apple's hit something like 20% of their materials being from recycled products. This is a significant number and is much better than these things sitting around taking up space.