I'm only speaking for my ATT experience, but financing thru Cellular usually requires either 1) a contract for (usually) 3 years; or 2) an additional monthly charge for the "privilege" to upgrade after paying 50% of the phone off. In order to take advantage of any "deal credits" (like getting $830 for an iPhone 12), we have to keep the upgrade phone for 36 months because the credits only come monthly, not all at once.iUp is the exact same thing as financing a new iPhone and trading the old one in every year w/ monthly AppleCare+.
I don’t think there are any other advantages or differences?
IUP is a loan (and a contract) but not a 3-year commitment and you don't have to pay extra per month just to be able to upgrade after 50% of the phone is paid off. This, while also including AppleCare+.