

I was trying to think of a good real world example, but couldn’t think of anything. But if you were to think of it as Google docs. You could just copy every doc to change it, but if you’ve shared it with people then you will have to share it again. It also takes up a whole lot more space to do that, sure you could delete those old ones but that takes some work too.
A place where this type of DB really shines is in messaging. For example Discord uses NoSQL. Each message someone sends is a row, but each message can have reactions made on it by other users. In a SQL database there would be 2 tables, one for messages and one for reactions with a foreign key to the message. But at the scale of Discord they can’t use a single SQL server which means you can’t really have 2 tables and do a join to find reactions on a message. Obviously you could shard the databases. But in NoSQL you just lookup the message and the reactions are just stored alongside it, not in another table, making the problem simpler.