Not fully.
It was only one season (for us, anyway) and we were stuck in the Lowland League.
Spanish sides, for example, are allowed up to the Segunda Division - if their teams are in La Liga. Villarreal B currently play in the Segunda Division.
It allows them to get a lot of experience, against men.
I actually think it allows us to develop the tactical side of their game internally, instead of farming them out to the rubbish we have in this country, which doesn't teach them anything that is useful to us. That's just me, though.