See dear all the south Indians , especially from Tamil Nadu people use to worship these Gods. especialy those from schedule caste people use to worship. but for some brahmins ayyanar also worshipped as Kuldevta. Muneeswaran, Ayyanar, Madurai Veeran or one way or the other way related to Lord Shiva. more over, Ayyanar is the person who keep watch on the particular area where he is installed. it is said that even at night , he use to walk and see the welfare of the people and hence he is called the watch dog of the particular area. i hope i am correct. but i do have my own doubts on this.