It is possible that even masked vectorised branchless code is susceptible to side-channel attacks based on power consumption, nor would I rule out timing attack

It is possible that even masked vectorised branchless code is susceptible to side-channel attacks based on power consumption, nor would I rule out timing attacks if you can somehow get subnormal or exceptional values loaded. Is it a joy to code in this style? Perhaps. Is it a silver bullet? It is not.