I mean, many countries are switching to turbofan based ASW/MPA aircrafts so I imagine it has some value that turboprops don't. And in fact, to me it's not a question of if China will do it but when, and I imagine the answer to that might be soon. IIRC there was a nice graphic floating around here that depicted the C919 being adapted for various special mission roles like the B737 did.
well, that depends on what platforms you have available. If the most obvious platform is 737, then you pretty much has to with turbofan aircraft. China has Y-9 platform, which is the most logical size for this category, so it's going with it.
Now, it is possible C919 could be adopted for special missions with PLA once it has a fully domestic supply chain, but we are not there yet. And more importantly, it's not clear me to why C919 would have better fuel economy than a next-gen turboprop aircraft that is likely to use hybrid propulsion?