This mode is ideal for managing small amounts of Monero. You have access to basic features for making and managing transactions. It will automatically connect to the Monero network so you can start using Monero immediately.
This mode will use a remote node whilst also syncing the blockchain. This is different from the first menu option (Simple mode), since it will only use the remote node until the blockchain is fully synced locally. It is a reasonable tradeoff for most people who care about privacy but also want the convenience of an automatic fallback option.