It's the kind of thing that works nicely in theory but is not really practical given the volumes of traffic that ATC have to deal with
CDA's are encouraged by airlines to save fuel. CDA's are encouraged by airports to reduce noise. There are many airports in Europe where it is mandatory and the ATC arrivals are designed to achieve a CDA. Either they put speed/Alt at the apt's on the STAR or they have an IAF with speed/ALT and then radar vectors with distance to touchdown info and they expect a CDA. It works at busy airports who have designed their airspace for such techniques. The volume of traffic does not affect it.