It is a fairly caste-like system. Psi-Warriors and Psions can be trained and controlled in government run schools. Wilder fluff indicates they always develop naturally, so there's less control over who becomes one (though an elan Wilder is certainly possible, they prefer as few random elements as possible). As for Ardents, they tend to eschew religion and the elan power structure in my setting is partly dependant on their elans-first, humanity-second, everyone-else-last dogma.
Anyway, Psychic Warriors tend to make up the military and peacekeeping sub-caste of the elan caste and Psions usually operate other parts of society. A religious Ardent Elan might be a high priest, but most elan religious officials are still Psions. There's just more of them. Also, I tend not to assume certain rules abuses* are being used unless I want to explore that concept specifically
*That sounds more accusatory than it's supposed to. What I mean is, everyone having Psychic Chirurgery would be an interesting world to explore, but requires a little more meta than I wanted or was going for.