actually makes sense, usually you run out of prots not of vials, so if they make the SB system only with prots will be nice, then in events put something else but not vials.

Currently I have on my Samehada 3 Y+1 and I have 400 prots but I know they won't be enough to get him full SB so I don't spend.

On Edo Minato I also have 3 Y+1 and probably spent 500 prots or more

Here's my personal experience

Minato - 120 protections - still missing the mystery breakthrough

Kushina - 130 protects - missed getting chase, but got the frags for free from events to max sb her

Killer Bee (8 tails Jin) - 150 protects - missing standard BT

Roshi (edo tensei) - 150 protects missing passive + mystery (RNG was crap)

GNW madara - 300 protects missing standard (I almost wanted to rage quit after this)

So yeah... either give more protects or fix RNG