I got the potion for an alt. As said, you get mounts and minions you get through the MSQ. This does include the unlocks for the HM primals, but not the extreme versions. Same for the HW version.
I've been finding there's a LOT of unlocks to go through. From the whole crystal tower series, all the extreme level 50 primals, the level 60 primals, the sky pirate set, Alexander, Warring triad, ect.
Not to mention the whole anima weapon series, although things are mostly streamlined in that a lot of the harder to get items like the crystals and such are now buyable with poetics. That said, you still have to run through dungeons and crank up the light in the weapons.

I said this to someone else, I'll say it here. They could stop putting out content for this game from here on out, and I'd STILL be working to do everything in it.
But then again, I am a slowspokie