Bali Peetam, of a Hindu temple - What does it highlight?

In a Kumbakonam  temple, Bali peetam., 

Bali peetam, Thirumala temple.

 Thirumala Balaji temple, Bali peetam.

Almost all Hindu temples, regardless of their affiliation whether  they are Shiva, Vishnu and Goddess Shakti  temples  across India have  a Bali Peetam, one of the important parts of Hindu temple architecture. Normally it is close to the temple flag pole or Dwajasthambam that faces the main shrine.  Dwajasthambam  is often referred to in Tamil as kodimaram. The tradition has been that exiting devotees after prayer at the temple normally would prostrate on the right side of the flagpole and Bali Peetam.

Bali peetam is  a sort of dome-like structure made of hard stone - granite  and is set between the flag pole and  Dwajasthambam of the temple.  It is rare to see the flag pole outside the temple premises. Shilpa Shastra says Bali peetam can be made of wood or normal construction material.  Its presence is more conspicuous in south Indian temples than in the north.  The word Bali Peetam has roots in Sanskrit meaning Sacrificial platform or pedestal often carved with lotus flower image 
 with petals carved around its base. Most of the Hindu temples have only one Bali peetam and a few may have one or more, the one facing east being the  main object of worship and veneration. 

As part of  daily puja rituals  in the morning, in particular,  in the sanctum  priests offer prasadam (Naivedyam) specifically prepared in the temple kitchen (in Tamil Madappalli) to the main deities, angles,  kshetrapala, etc., and then at the Bali Peetam.  Devotees finally get the blessed food-offering. The main use of Bali Peetam is to offer the Naivedyam(Bali) to all the Avarana devatas of the temple to appease them.

Lots of people are under the wrong impression that Bali peetam  at the place of worship is the  the place where animal sacrifice was done in the past. It is totally  a misconception and the concept of bali is  misunderstood. Bali peetam was never used in the past for animal sacrifices. Nor does it refer to spilling of blood on the peetam. Animal sacrifice was and is a taboo on the temple premises. Bali Peetam is used  to offer the Naivedyam (Bali) offerings to all the Avarana devatas of the temple and nothing else. Avarana devatas  are  those installed in the area surrounding the main deity'. 'The garbhagṛha sanctum is generally surrounded by āvaraṇas or enclosures whose number may vary from one to seven' The offering made is called Bali Bhukku and is meant for gods  and not for humans.

The primary purpose behind placing Bali Peetam in temples is to surrender one's arishadvargas - negative thoughts and enter the temple with a pure mind focussed on the presiding deity in the inner sanctuary. There are  six things that prevent us from getting Enlightenment and Moksha. They form the stumbling blocks that need to be tackled to reach highr levels of spirituality.  Kama (Lust), Krodha(Anger), Lobha (Greed), Moha (attachment or love), Mada (Pride), and Matsarya (Envy) will try to cast a spell on you and you have to go past them without getting affected by any one of them.   Here The   bali peetam is the altar on which you get rid of all evil and negative thoughts that will never let you progress in your life. Once controlled and surmounted you are blessed with contented life.

The spiritual and philosophical connotation is as per Agama sastras, before entering the place of divinity and sanctity  it is a must to get rid of ego, arrogance and other negative traits mentioned earlier. The mind must be pure and free from  all evils. This is the reason why devotees  prostrate in front of it and flag pole in order to be humble and submit themselves to the edict of the almighty.

It is to be borne in mind that while leaving the shrine after prayer in the sanctuary, a devotee must pray in front of the Dwajasthambam and Bali Peetam as a token of your total surrender to him and the unabiding trust you have in him. 

Devotees doing  Pradakshina  around the temple  will never miss  Balipeetam, Dwajasthambam, and the Vahana mandapam if they were present inside the temple. Further, they ought to know that before god everybody is equal. Opulence, exalted status and power will not put the devotees above others in the abode of god.

The food kept on this sacrificial altar  is meant for the  Avarana devatas and  and should not be  tasted by the devotees. Further, no one should sit or stand on it and offer prayer. In rich temples Bali peetam is gold-plated as at Tirupati Balaji temple, Thirumala, Here the food - prasadam  is kept on the altar after offering food to the Lord and other deities. 
Shaiva Agamas mention  seven kinds of lingas in the temple namely  Shikharam, Gopuram, Dwaram, Moola lingam, Archaka lingam, Prakaram, and the Bali Peetam, the latter is referred as Bhadra lingam.