When you buy software, you expect it to break. That’s the reason you pay up for a support contract although one might argue mistakes in the software are really not your problem. Similarly, organisations rely on accountants for dealing with taxes. But when it comes to the life blood of an organisation, namely the data, it is expected that everything is handled by the person who knows Excel the best?
In our experience, having someone to call to when in doubt about a decision, preparing a presentation, writing out a project proposal, etc. is a valuable asset to your organisation.