Google API Client Library for C++ vs libcurl for sending HTTP request?

After installing google-api-client library for C++ on a Fedora 20 machine, I find out that it has external dependencies on libcurl (for example, setting up http proxy). I was planning to use google-api-client for sending HTTP request, mainly, HTTP multipart POST request. However, libcurl does provide support for multipart HTTP POST request also.

Could someone let me know the advantages of using Google API Client library for C++ over libcurl in order to send HTTP request?

Any suggestions/recommendations would be highly appreciated.

Thanks