Erik Darling points out one of the many benefits of normalizing tables in a database:
Looking at the design, there are two big problems:
1. There are “order” columns that are going to get a lot of inserts and updates
2. You’re going to be storing the same customer information over and over again
The more related, but not independent, data you store in the same table, the harder it becomes to effectively index that table.
My take on this is that the old adage of “Normalize until it hurts; denormalize until it works” hasn’t been operative for the past 15 years, when the SSD era began.