I would say that if you change a physical address it makes sense to be there in person to prove it. This could be seen as a kind of security/verification feature.
Some countries confirm it by sending a document to the address and you must respond with the provided code. Seems more secure than being present in an office?
Belgium checks this by sending a police officer to your address at a time you're likely to be home (~7:00 on a weekday evening, Saturday morning, or the like), regardless of whether you changed your address at town hall or online. The only reason more places don't introduce such features is that it's all done on the municipal level and not all municipalities have the same priorities.