I speak about the UK, which is what I know best.<quoted text>
If the churches keep more in taxes not paid than they spend on matters of values to the taxpayers, then they are a burden on the taxpayers. In America, this is estimated to be in excess of 71 billion dollars a year. I'm pretty sure that the churches don't spend nearly that on matters of interest to the general public, and I sure wouldn't take their word for it.
Churches, like the Church of England, have to maintain the many buildings they own.
They have to provide a stipendary (wages) for their clercy.
They have to subsidide parishes, pay gas, water and electricity bills and other expenses.
They support their own education centers for priesthood.
They finance their media, publish books, pamphlets, CD, DVD, educational material, etc...
Churches also financially support charities, their own and others too.
Churches conduct pastoral duties towards the hospitals, the hospices, the retirement homes, the prisons, the schools, the universities, etc...
I think the public purse is better off exempting churches from taxations than having to support them!
Just look at Germany, where the churches are state supported, and clerics paid by the government, it's an outcry every year when the collossal bill is discussed at the Bundestag! Church goers in Germany pay a special tax to finance the religious expenses afforded by the country. It's an endless subject of discord.
I much prefer the British system. We don't pay for churches, they are financed by voluntary contributions, taxations and the gestion of their portfolio.
I cannot comment about the USA.