Undoubtedly, being on the voting register will help in some way to build a better credit score. Being on the electoral roll helps to show a degree of stability.
The problem is, so many people for whatever reason, don’t or won’t register. This is despite the fact that it is compulsory for the annual voting registration form that arrives on every household’s doorstep to be completed by the occupants of the premises. Failure to do so can land the occupant(s) with a fine of up to £1000 and potentially, a criminal record. But here’s the rub, I suspect that very few Local Authorities prosecute anyone for failure to complete the form. Also one of the reasons that all persons of voting age are required to register, is so that they can be forced to attend for Jury trials. You can’t just get out of acting as a Juror if called else one risks being prosecuted, not unless you have a bloody good excuse that is.
The fact is, there are some people who just don’t want to be found, cite personal privacy issues, can’t be bothered or are just plain anti-establishment. Anyone who doesn’t register to vote, has no right to complain about who gets into Government or who runs their local authority. Personally, I’ve been registered my entire adult life at every address I’ve ever lived at