It's a way of following the rules of Islam by using a different name for the same thing basically, it makes them feel better about it and like they are not committing any sin. So, some religions do have some economical rules and that is why it could be very important difference for some people.
That is how faith tries to help those who have a guilty conscience and also why many criminals gradually look up a spiritual path in later life in an attempt to redeem themselves. But following rules if your own choice. You can be very strict about your own religion but in reality be a complete non-follower, something like a mole in the system. After all these rules have been created by humans and will always be broken by humans.
On the other than using them as a method to call investors to support a project is wrong. Those who are successful traders know these things and have learnt how to avoid such coercion.