Currently, when a hardware wallet is attempting to clear-sign a transaction which includes a data suffix, the transaction either has to be blind signed, or sometimes the transaction may not be able to be signed at all.
ERC-8021 standardizes how data suffixes are structured, which means ERC-7730 could parse that data and omit it when verifying the transaction. Wallets which implement ERC-7730 could also optionally display this additional data.