Why is Dr Brawn so bad?

He is not remotely worth the gamble because it feels like 8/10 times he will do the full -30 but the positive effect is only +15, so even if you somehow got twice as many positive experiments as you did negative ones it would still only be enough to be at zero. He would need to have a positive experiment rate above 50% to make him worth it but it’s not anywhere close to that. On top of that, even if you have a pal with zero traits, you can get a positive experiment that adds a good one but then the next negative experiment will just remove it again and replace it with something bad. I’ve been doing every experiment on the same galeclaw every day and he is now sitting there with full 0/0/0 IVs and 4 red negative traits.

Am i missing something or is Dr Brawn really that bad and unusable?