We've been working on a user-requested feature: sync-to-chaintip
Other full-node Zcash wallets would not be usable until the wallet fully syncs to the blockchain. If the user has not accessed their funds in a while, that could mean waiting hours or even days for the wallet to start up.
Zenith was designed with an incremental sync to avoid this issue. You can start the wallet, browse your wallets and accounts, and use QR codes to receive funds even if your wallet is out of sync. The automatic periodic sync only scans the next batch of 100 blocks, avoiding locking the wallet for an extended period of time.
But what if you do want to have the wallet sync completely? Our next release will include this feature.