Why do Catholics portray the cross with Jesus still on it?
The Catholic use of a “crucifix” (cross + corpus) vs. a “cross” (cross without corpus) helps to remind us of a very important fact: the suffering and death of Jesus, while indeed necessary to atone for our sins and was endured for our salvation, was a real suffering and death in every sense of the word. Although there is nothing wrong with using the symbol of the cross alone, I believe that it lacks a critical faith message if exclusively used: that without the suffering that Jesus went through during his ordeal of Good Friday, as must we all in one way or another, he would not have been able to arrive at the glory of Easter Sunday. This helps us to remember that, when we too go through our sufferings and our eventual death (just as Jesus did) maintaining our faith in him, we are also promised that (just as Jesus did) we will rise again and join the Father and the Son in perfect and holy union.