>>20090374UUfag here. I wouldn't even use it in UU. Sure it's an almost decent stop to Fighting types, but then you have to deal with the physical Fire types that will laugh at your defenses. Slowbro is strictly better, since it has better mixed defenses, a tying that puts a full stop to both Fighting and Fire types, a good dual STAB, the ability to buff with Calm Mind, and reliable recovery in Slack Off. It also pairs extremely well with the other pink bitches in the tier Aromatisse, Blissey, Florges, Alomomola, and Amoonguss to create the Pink Core.
So yeah, I would maybe use Weezing in NU to burn physical threats, but nowhere else.