My understanding is that for crypto specifically it constant-time algorithms matter due to security implications, and those are only available when you use specific branchless assembly instructions, so it's not just performance
For example a RISC-V CPU implementing the Zkt extension is required to implement a whole bunch of logical and arithmetic integer operations with operand-independent timing. This includes the two "branchless move" instructions from the Zicond extension, czero.eqz and czero.nez.