I like this framing by Casey Winters on how to evaluate Feature/Product Fit when you release something new:

Feature/Product Fit has a third requirement that is a bit different: the feature has to improve retention, engagement, and/or monetization for the core product. This last part can be a bit confusing for product teams to understand. Not only do the products they are building need to be used regularly and attract their own usage to be successful, they also need to make the whole of the product experience better.

Any new feature is part of the larger product system, and our success metrics should take that into account.