So can I store LBTC on the Binance Chain? Then transferring from the mainnet to the Binance wallet is just wasting miner fees, isn't it?

Wallet BTC Staking Activity, waited a long time without tokens. Go check the dapp to see if the minting failed, manually mint LBTC, and then deposit LBTC into the Vault to receive LBTCv. (See image two, image four has detailed explanations, official event personnel said this approach is feasible).

Note: Users who attempted staking through the Binance Wallet app and failed can continue to stake manually on the Lombard DApp and still receive event rewards, but users who only minted and staked through the Lombard DApp will not be eligible for the Binance Wallet event rewards.

【Why the received LBTCv and BTC amounts are different】
LBTCv is a certificate existing in the vault, depositing LBTC earns interest, and LBTCv to LBTC is not 1:1. LBTC to BTC is 1:1.