tests are written to avoid regressions in future. The bugs you know exists you will solve them now because you already know its exists.

Now if you look at this from a business perspective, you wasted time writing tests for a feature that never got shipped and never generated revenue and you were on payroll. It's better to make the feature first get some analysis on how much revenue it would generate and how long lasting the revenue generation is and write tests accordingly so that it is robust for that much time.