You're effectively holding users (and especially their data) hostage by exploiting sunk cost fallacy, rather than letting the value of your product stand on its own weight.

Here is a recent thread on this exact topic with much more discussion about how user-hostile this is, and how it makes many assume that your primary goal is to collect data to sell rather than to help any individual with any benevolent task.

Dear websites, stop asking for ransom sign-ups https://news.ycombinator.com/item?id=36962502