Residual value on luxury cars is typically poor, because part of the justification for the price premium on a luxury car is being seen in something impressive, and a 3-year-old car is no longer so impressive.

So saying "for the same residual value percentage as the iconic Mercedes S Class, one of the finest premium sedans in the world" is honest but kind of deceptive. You'd much rather have the same residual value percentage as the much less expensive Jeep Wrangler.

This is basically a lease, phrased as a sale with the option to sell back, to take advantage of incentives that governments give to buyers but not lessees of electric cars. A nice option, but hardly worthy of the breathless marketing hype.