Well, I am all for more money in circulation. If the vatican or house of Saud or Mormons spend money for that, we could think of it as FDI....
PS - I am against conversion by bribing by anyone. Muslims getting converted to Christianity or any other faith on the false promise of better life is very very unfortunate.
More to the point, there have always been promises of tangible benefits in mass conversions - either promise of money, or promise of miracles, or promises of future success in life, or promise of eternal bliss in sugarcandy mountain in the afterlife, and so on.
If anything, conersion using money is better than conversion through force, which as we know has happened quite a lot.