Your data model is the heart of your business. Let's say you have a genetic product and require the user to upload their dna results and certain datapoints are taken and stored. If you decide later you want different datapoints and have not saved the original uploaded file you can't offer past customers new products.
Saving the whole file or not is an architectural decision involving cost tradeoffs, technology capabilities, and business strategy.
Which data points you put in your OLTP is the data model and, as you just painted an example of, throwaway when the use cases change. Later you'll want different data points or different relations. And then you'll evolve your data model yo serve that. If you did your architecture right, it will change much less than the data in your databases.
Your architecture can change.