Yes, their only function is to choose our presidents and vice-presidents every four years. But, that's a pretty big job.
I assume that they try to make legal choices and understand that they are required to choose only persons qualified to serve. A lot of electors have surprised people with their votes. It could very well be that some of them did not vote as people predicted they would because they found there to be eligibility defects in some candidate. The Constitution does not require that they explain their votes.
They serve a ministerial function. They have no authority to inquire into the age, citizenship, or residency requirements specified by Art. II. They vote. Period.