A good rule of thumb is perlite encourages drainage, and vermiculite encourages moisture retention.

I notice that many nurseries use perlite because they have someone who's literal job is to water those seedlings, so the soil is kept consistently wet. For me however, between balancing job, garden, and life, the seedlings tend to get neglected, and so I need them to be able to handle a missed watering or two. You do then have to be careful not to over water with the vermiculite, I've had issues with dampening off and root rot.