So is the first part a Passive ability then?
I really like the card, although I'm kinda struggling to see uses for switching weapon places. I suppose switching vulnerability from PC to CC, but that's about it.
In the unupgraded case, it allows the juggler to work with rare weapons as well, at the cost of an extra turn or additional juggler.
For the upgraded case, its partially there for consistency. It also makes the card a little less sensitive to the order in which you animate things.
E.g. you can animate a non-rare weapon to make room for a rare weapon, then when a creature buff comes along (adrenaline, blessing, etc) you can swap the non-rare and rare weapon so that you can buff the rare weapon.
Example:
I have a novice juggler and an equipped dagger
I play a vampire dagger. The juggler flys the equipped dagger that got replaced.
Next turn, I swap the flown dagger with the equipped vampire dagger and cast blessing on the vampire dagger.
etc.
The idea is to encourage decks to use a large number of non-rare weapons with a handful of rare ones sprinkled in.