I think it is more privacy and convenience then the fear of them running away with their money (although many bitcoiners prefer to have 100% control over their funds 100% of the time, especially after what happened with gox).
I agree but if they change to weekly, most of them won't care about the payment to Bit-X.
By having to provide their phone number as well as being asked to provide personal identifying information (although there are ways around actually giving this) people are giving up a lot of privacy, privacy that holds a lot of value.
I heard Google 2FA will be added soon.
Edit:
There is absolutely no need to provide any other personal identifying information than a phone number to signup and withdraw any signature earnings.
Forgot about this.
-MZ