What's the difference between importing and sweeping a private key?
Exodus is a Hierarchical Deterministic wallet. This means that all of your addresses and private keys are derived from your wallet's 12-word phrase.
When you use the Move Funds option found in the Asset Menu, you are able to enter a private key in order to move the funds held by that private key over to Exodus.
Importing a private key into Exodus isn't a true import since it doesn't bring with it the address associated with the private key. Exodus uses the private key to "sweep" your funds from the private key address to your Exodus address. Your Exodus wallet is effectively using the private key to create a transaction which involves sending the funds from one address to another.