Reasons include the idea that ambitious research needs significant resources devoted for its execution and the reduction of administrative and overhead costs on the funding body side.
Small Science helps define the goals and directions of large scale scientific projects.
In turn, results of large scale projects are often best synthesized and interpreted by the long-term efforts of the Small Science community.
In addition, because Small Science is typically done at universities, it provides students and young researchers with an integral involvement in defining and solving scientific problems.
According to the Chronicle for Higher Education, James M. Caruthers, a professor of chemical engineering at Purdue University, data from Big Science is highly organized on the front end where researchers define it before it even starts rolling off the machines, making it easier to handle, understand, and archive.