It casts lots of things. FoW, ravenous trap, gush.
It gives you an improved scry 2 (which in grindy blue matches is better than a 2/1 body), feeds delve and doesn't target (which is great against non-definitive grave hate).
I don't know if it's better than snapcaster in vintage. I'm trying a 3 snap/1 JVP/1 briefing splash in URw mentor, and so far it has proved to be very useful flashing back a ravenous trap and digging deeper to good cards. The problem in this specific deck is the lack of finishers (3 snap/1mentor, besides the 2 JTMS).