Maybe yes, but still:
it allows you to add it
it's still a bug/defect that limits modding
this is a workaround that will work only if:
the trait is not a trait that works only when added during character creation
the trait supports hotswap (i.e. it can be added on the fly and its effect will apply immediately)
you don't want to add it to a vanilla profession (otherwise, due to a different bug, you'll break preset saving, randomized character creation, resetting the traits)