Staff Stats Confusion? Help!

Hello everyone!
I recently made a purchase on a staff, but I am confused on whether or not it is worth it.

The staff main stats are as follows:
Anniversary Staff V
-2% INT, +7% MATK
2 slots
ATK: 143
Base: 142
Refine: 0

In my mind, I was thinking about saving for Black Crystal Beasts and hoping it nullifies the negative effects of the -2% INT, since it has 4% MATK on the crystals, making it an extra 8% + 7%.

I would like your input and please elaborate in a very detailed fashion!~
PS: Arrow Mages Top DPS?

 

no :")
might as well get anniv V staff int+7% matk+7% int+13 1slot staff, and slot w imiticia xta

example u slot ur int-2% matk+7% staff with ecb and imitacia, u get approximately 9% extra matk.
but if u get int+7% matk+7% int+13 1slot staff, and slot w imitacia xta, u get approximately 5% extra matk, but u have 9% +13 extra int compared to the anniv 2s staff u bought.
so to sum up, if u choose to buy the 1s staff, u get int+9%,+13, in exchange for 4% matk, which is much more worthwhile .u.
bascially thats abt 35 int (might be higher) in exchange for 4%matk
35int=approx 140 matk or higher if ur char stat is int255
4% matk on 3k matk (which is hard to reach) only gives 120matk
so clear winner is 35 int, or rather, anniv V staff int+7% matk+7% int+13 1slot staff x-x
so sadly ur staff is not worth it x-x

 

Thanks for your response, I'll try to sell mine.