Again, the flat decks are not the equation here. The fact they spent so much money developing J15DH and then &15DT show just how important it is in their entire EW effort and that includes passive detection and general analysis of sig int. They don’t have another platform in their naval air wing that does this. At least not until KJ600 is available.~3-5 years in the future, when the second 003 hull (or first 004) will reach operational status it will start turning true.
But not now.
Right now PLAN has 2 operational carriers, 6 flat decks overall, +2 more working up. Out of all these, just 1 unfinished ship will get to fully employ carrier EW; 001s are hard capped to 14 aircraft in the air by spotting limitations. You can include them (both into strike packages and doing their own supression missions in interest of other operations), but there's only so much you can do with this number of aircraft.
And it is a force multiplier. But neither primary capability nor the most important aircraft on the deck.
Remove it, and carrier air will keep it's current functionality almost perfectly.
in terms of electronic attack, you need something like this to extend the range of attack against adversary ships so that PLA ballistic missiles can be more lethal. PLAN carriers are an extension of their entire attack force including RF