The overall shape of the objects we send along with each API request or receive back as part of API responses will impact much more than just how data is used in applications, and will define quality, reliability, and overall security of APIs. Setting minimum and maximum values, identifying regular expression patterns, and filling out the shape of schema properties is always a wise investment.
The shape of schema properties is just as important of the design of the API paths, methods, and operations. Schema property shape leaves the overall shape of API requests and responses wide open, or ensures they are always a well known schema. It is easy to overlook the many properties in use across APIs, and cut corners when it comes to the shape of them en masse, but the shape of our schema must be well defined otherwise we are just inviting in trouble.