Solaris 10 - Why shell limits needs to be increased to run oracle database? Shell limits affect shell and scripts running shell like bash.
Oracle's requirements (https://docs.oracle.com/cd/E11882_01/install.112/e48357/pre_install.htm#SSDBI1182 - section 2.10) is to modify these values to a given minimum and to set them to unlimited in production environment.

If the oracle database run a set of binaries, how would changing ulimits affect the database?
Oracle might be binary, but it will still initiate system commands which in term could involve shells. On UNIX systems, the ulimit command controls the limits on system resource, such as process data size, process virtual memory, and process file size. It is also mostly the users processes affect parent processes. So the parent processes manage the users. Normally ulimit is inherited from the main user, so allowing you to set a value for Oracle might be in the interest of your system administrator. In Solaris it is ulimited. ulimit -Ha and ulimit -Sa will show the hard and soft limits. Good rule of thumb is to ensure the soft limits do not exceed the hard. But unlimited for a dedicated Oracle server would be better.