A religious Altar is what you see in the church with the image of christ on a crucifix mary etc the trinity which represents christianity. That is an religious ALTAR. What is being mentioned here is how people choose to hold their registry wedding and ‘religious’ ceremony in a non religious environment and is where the bride and groom stand at the front or sit where everyone can see them. What is wrong with having it that way? The word altar isn’t limited to just a religious context only. Its like saying why should the bride walk down the aisle towards her groom on the wedding day.
Anyway i think its a great idea but i get nervous quick hence going to aim for a intimate nikaah at home and save the nerves for rukhsati day.!