After letting this question get mulled over by google translate for a couple day I think I might know what you are asking.
First option: Asking which you should play; paly or psi?
Answer: Depends on preferred play style, if you like to tank or at least enjoy some melee combat getting up close and personal, go with the paly. If not, go with the psi.
Second option: Asking why certain classes only have access to certain weapons/gear.
Answer: The game is set up to allow each class to have a specialization in gear so its not a whole party trying to roll for the same gear. Paly will use melee plate, psi will use caster leather.
If there's a third option Google hasn't deciphered it yet.