The problem with CX now is that they don't let you change your FFP after booking, you can change it once when physically checking in at the airport, and to use status benefits you must have the status FFP in the booking.
If you fly CX particularly in economy with any regularity you would be better off crediting them to other oneworld programs. For at least 10 years it's made more sense for me to only credit QF flights to QF and all other flights elsewhere - previously CX and BA but since BA destroyed its program I have moved to AY.
In the past if you had QF status there was no issue with crediting a CX Y flight to BA or CX and then flashing your QF WP card for lounge access etc, but now you are forced to credit to CX.
Looking at all my past CX economy flights, the most common booking classes are L, M, Q, S, V.
Q,S,V earn nothing on QF.
Q,S earn 25% on BA.
L,M,V earn 50% on AY which is worth a lot more to me than the pittance you get from QF.
K also gets 50% on AY but slightly higher on QF. Usually taking the avios is still better. But to get up to class K, the fares are already quite expensive and you'd only really choose them if you are stuck with particular dates.
I don't think I've ever bought a ticket in CX Y,E,B,H, sometimes it would be cheaper to buy two non-refundable tickets than one of those.