The very thought of a regular police officer not giving in to his demons is pretty much infinitesimal at this point in society. Of course, there are mostly good, moral upholders of the law, but some of the "laws of peace" can be used for evil purposes by other officers.
The use of civil asset forfeiture by police officers is suppose to be a way to seize property that may be involved in a criminal act. There is a temptation for officers to take items that they desire for themselves. This behavior is a natural outcome of the law and it is too easy for police officers to justify that they took it away from criminals.
Although civil asset forfeiture makes sense in theory (and likely did in the past, as well), it seems that these days it's just an excuse for police departments to further fund their budgets. I once watched a video in which cops busted up some sort of operation, and on tape you could literally hear officers calling out 'dibs' on the totally unrelated musical equipment in the house. So while this is 'legal' it's certainly not 'moral' or 'right'.
Like many law enforcement policies, civil asset forfiture is one that is easlily abused by the police. THey can take items that were not used in a crime and hold them indefinately for unclear and imprecise reasons. Without clearer laws and rules about this, this is a law that can be abused.
Tho the evidence of, or obtained from an object may be desired by law enforcement agencies, no specific officer has possession of items in question. For instance in the case the question sources, I highly doubt an officer is using the iphone for personal or police use.
Problem is, without knowing what the charges were or the reason why the iphone was needed as evidence, it's hard to say whether keeping the iphone is justified. For instance, if they are or plan on going through the phones call history or data that could assist with other cases. I can see how they may want to hold onto it instead of risking the phone being destroyed by the owner. For instance, if the iphone was used by others to aid them in criminal activity, information stored on the iphone could lead to convictions even if the owner was personally not involved. Police may not want to disclose information about this case as it may jeopardize the investigation.
No, civil asset forfeiture is not a legal way that law enforcement officers use to take items that they desire. It may, however, be a way for them to get assets that they do not want another person to have for some reason away from them. It does not make sense to believe that there does not have to be a good reason behind the forfeiture.