US Republican lawmakers urge SEC to rescind accounting rule for digital assets.Letter issued by Congressional coalition, including House Financial Services Chair Patrick McHenry and Senator Cynthia Lummis.Criticism mounts against SEC's Staff Accounting Bulletin 121 (SAB 121) for deviating from accounting standards and creating confusion.SEC's recent grant of exemption to BNY Mellon could signal a shift in approach towards traditional banks in the crypto space.