Energy weapons could be calibrated to damage organic matter only, or maybe to not damage certain materials, which would allow the ships to remain unharmed. If they are wide-beam, or have that option, then having just a helmet might not be enough in a firefight. Full body armor might be too restrictive, though. The mesh jacket makes sense.
I guess I’m thinking of Dune, where energy weapons are basically useless due to shields and such, so they use regular old iron knives and swords, but I don’t think that really fits our universe.