Using JsonSerializerOptions with source-generated JSON deserialization is not immediately obvious, but it's a powerful tool for controlling the deserialization process. When deserializing JSON data that doesn't match the exact case of the C# property names or requires mapping an enum to a string, using JsonSerializerOptions can provide flexibility and accuracy. The problem arises when trying to deserialize JSON with string values for numeric properties, as source-generated deserialization code does not support this. By using JsonSerializerOptions, developers can overcome these limitations and achieve accurate and reliable deserialization of their data.