From one of the reviews of the mobile app: "now, wifi sync is no longer available. The developer has seen fit to force you to sync your personal, financial information over the Internet via Dropbox."
There's a problem with having to use and trust Dropbox, however. It's a company that's consistently proven that they can't be trusted, both in terms of truth and competence.
Thankfully, with sane encryption you don't need to trust them. (Or any other cloud outfit).
They're more than welcome to distribute and analyze as widely as they see fit, the few hundred megabytes of random-looking data sitting in my account :)