Assuming the flash drive is reusable, that's not too bad of a deal for $30. That said, being crammed on a 4GB drive naturally means that the films will be in standard definition -- a deal breaker for many, I'm sure. Perhaps HD-friendly films will be offered on larger drives at a later date, but there are few details about the companies' future plans.
It seems to me that the people who would be most interested in this offer, probably already own a Blu-ray player. Would you pay $30 for a film stored on flash memory?