The legal process is nothing to do with the victim, callous as that sounds. It is not about getting justice for the victim and certainly nothing to do with fairness.
The defendant is in the dock because he is suspected of committing a crime, or has admitted to committing a crime and for that he must be punished. Criminal cases are always R v Defendant, not Victim v Defendant. The defendant has broken the law of the land, he has committed a crime against the State and he will be punished even if the victim does not want to press charges in some cases. Equally a case may never come to court no matter what the victim wants because the Crown says so, usually it is the CPS who make that decision.
So the victim doesn't matter. The defendant will be sentenced in accordance with sentencing guidelines taking in to account the DEFENDANT'S state of mind and any mitigating circumstances.
This leaves the victim, or the victim's family in the case of murder, feeling somewhat apart from the proceedings and ignored. To appease them it was decided that victims could make impact statements to give them a voice in the court. Does it make a difference? Not to the outcome of the legal proceedings but maybe it does help the victim to have his say and maybe it does help the defendant realise the enormity of his crime.