Think of it this way. If you are in a concert hall listening to a vocalist live, the hall itself has a certain reverberation that you can hear from your seat. In a recording studio the vocalist booth is usually dead sonically. In other words all reverb is dampened with acoustic panels. Reverb is then added electronically to mimic the sound of a concert hall (which adds depth and spaciousness) at least to the degree the recording engineer deems appropriate. The sound of a concert hall requires a huge room acoustically designed. Since that is not feasible in a studio setting electronic reverb is used. The critical aspect is how it is used, it can be good or it can be over done which affects the final sound of the recording. Hopefully the recording engineer has has a good ear!
Reverb
As my system slowly works itself up the food-chain, I can clearly hear more reverb in recordings - particularly with vocalists. Why is it added with singers who have great voices? With studio recordings, the room acoustics should be fine. For that matter, they might even be in a booth. (Reverb makes sense in recordings with not so great voices.)