Why indeed? On the team I work for I am often called upon to help with technical problems, despite the fact that I escaped from the help desk some years ago and went on the road.
The usual reason given for calling me directly is that it is quicker to call me; this can be a bit of a bind if I am busy with a customer or driving to another call and can't give their problems my full attention. I can sometimes help but often ask them to call the Help desk, not because I wish to be unhelpful but because simply, it isn't my job guess at the reasons for system failures, given that I have no more access to system information than other members of the team.
It can be helpful to check with fellow team members to see if a problem is confined to one person or whether it is a general problem but ultimately we need to call the help desk to get the call logged and brought to the attention of the correct support team.
The other reason for reporting problems to the help desk is that if we continually fix problems in the field they will never know that the problem exists; if they don't have the problem in their sights then we will always have the burden of dealing with it ourselves.
When our PDA phones were first adopted they used to lock up and crash several times each day. We would reset them and carry on but this was very time consuming and we were losing valuable time and data in the process.
We were complaining about it to the regional manager and he went off in search of information. To our surprise, he didn't have any record of unreliability, the help desk had no fault logs, and there was no paper trail leading to or from the problem.
We went to the supplier of the PDAs and complained about them. At first they refused to acknowledge the problem, so we started to call the help desk every time the devices played up. Within a few days we had a great deal of reported information and the vendor started to take us seriously.
A field visit to one of our engineers convinced the vendor that there was a problem with the PDAs and we were soon re-equipped with a better one. When the evidence was anecdotal, it wasn't given much weight. As soon as we logged it all and the help desk was able to collate all the faults from all over the country, the pattern of the faults became apparent. That is why we should use the help desk; even though we can often do a quick fix ourselves it may not be the best thing to do in the long run.