It's not weird at all. It's also called the "Must Have" Metric which defines if your product is a Must Have vs. Nice-to-Have. Must Have means your users can't live without it. This is the first state of Product/Market Fit. If you have can find a scalable channel then you have the second stage of Product/Market Fit.

Not all products need or have retention. Some amazing businesses are 1-time or products people pay for but don't need to use or actively engage with.

e.g. Universities, Courses = 1-time use Stocks/Investments = buy them and don't touch them until you sell Insurance = buy it and don't touch it until you renew 1 yr later Plenty of other examples

But every product should be a "Must Have" if it's going to grow.