You're going to want to run analytics, and to do that you need comparable data. Legacy data was a huge problem for the e-commerce giant I used to work at, even

You're going to want to run analytics, and to do that you need comparable data. Legacy data was a huge problem for the e-commerce giant I used to work at, even in The SQL database with a schema. NoSQL would be a silly non starter for any serious data modelling effort after a couple years of migrations outages, and code changes.