Advantages of SPServices?

1. Allows anonymous access
2. SharePoint functionality is exposed with the SOAP Web Services,
3. Works cross-site and cross-domain 
4. Client side coding
5. Familer to any other platform like javascript,jQuery angular JS
6.  assuming that the authentication model you are using allows it
7.  Simply pass the required parameters to the Web Service operation,
8. Built on top of jQuery, which is very good at ensuring cross-browser compatibility
9. Regularly updated and refined to be compatible with new versions of jQuery and to add new functionality based on user input
10. Works identically in SharePoint 2007 and 2010