Also, anything related to finance is always hot. And this comes back to the same thing I made in the above comment, why should an end user who is just trying it out risk all of this? It's like telling a stranger a secret of yours. You wouldn't just share a secret with a stranger just because they say "trust me", would you?
It is the company who needs the users attention, not the other way around. The users shouldn't be punished for the same.
this risk will always be present. Choosing a well known processor will reduce it quite a bit imho.
If you're asking why a user would take on this risk, i would say that they are getting a "free" trial in return. By having to take on this risk, the user is more conscious of using the product, and cut out the people who would just kick the tyres.
Again, the burden should not be in the shoulders of the end user. There is no reason for the company to ask for credit card other than data sharing, other dark patterns and spam. Like many have mentioned, spam can be dealt with better by other means. These are companies who have tried it out. I don't know what else more to say. :)