This new mechanism has the advantage of putting a hard monetary value floor on miles.

Sure, when redeeming miles, the current value roughly ranges between 0,005 to 0,01 €/mile... but when promo fares exist, the rate can go as low as 0,0035 €.

The constant opportunity to secure 0,004 €/mile should help slow down miles inflation.
I see it as a win-win. The airline can clean up its bottom line (I'd rather see them to this than find new creative ways to save cost on F&B); those with 6/7 figure miles accounts can at last use them on something else that random merchandizing, and miles inflation will be harder to implement when there's the money redemption option floating around.