False, I know firsthand. I had a 3G, upgraded to a 3GS a few months ago. I was able to log in using my google acct (which is what was used originally to purchase some paid Cydia "apps"). I logged in using my google acct on the new phone and was able to download my purchases again.
The purchases aren't linked to the specific phone, they're linked to whatever account you originally purchase them with. I think google and facebook are the only two options, but I may be wrong.![]()
you are wrong, there are various payment methods on cydia, ie. paypal, google checkout, amazon, etc.
Most purchases are tied to your device, not your purchasing account, so you won't be able to reinstall all of your paid cydia packages without first contacting the developer.
In your case you just got lucky and the dev only tied the purchase to your google account rather than your specific phone.