Docile Dongou has been in Barcelona B for a while now yet every other striker that has came and went (Sandro, Sanabria, Munir) has outshined him.
Let's be honest and say that the only one out of those three that he compares to is Sandro. Even then here's a comparison of each of their ratios in terms of goals per minutes played:
Dongou: ~.0039 goals/minutes played
Sandro: ~.0049 goals/minutes played
And that with Sandro not even having had an entire season of acclimatization time as Dongou did. Dongou just does not cut it, needs to get loaned out but I suspect he'll end up probably rotating between clubs and loans indefinitely a la Bojan. He showed some better form towards the end of last season but Munir is just a far better goalscorer and a far better footballer in general so developing him is the way to go forward, something the coaching staff clearly recognizes.