I agree that many if not most of these buildings are ugly. Many should be preserved though; normally this is done by a decision of a local body including architects and other experts.

These things aside, for someone visiting Crimea, for example, these buildings do matter a lot. They basically move you in time. You can actually get a strong feeling of things that you know maybe from very early childhood or mostly from books or documentaries. It is very, very different from anything you could see in the West.