Salvia is very worthwhile and is one of my favorite 2 Entheogens.

That said it has much less of a recreation potential than some other drugs like dmt.  This is because it is a plant of sorcery and witchcraft and indeed a certain level of darkness is present. People can use it if they will, but I believe it to be a sorcerers plant and most that use it will not be called to use it again.

Also salvia has a steep learning curve and the first number of times may be hard to make any sense of.  It's only with practice on how to maintain absolute focus while entering the trance that you can start to work with it in a positive wAy. Once you have started the relationship and seen it through a bit it makes much more sense and you can gain much from the plant.

Salvia is remarkable in its consistancy I would say the most consistent plant there is.  9 times out of 10 you will pick up directly where you left off. This makes it easier and easier to learn from salvia.