I dont think they fought Blackbeard since they are shorthanded. Their commanders were not there and kuma, one of the most underrated character, is one of the strongest characters is captured. In reverie, its still not clear what happened. But their only mission there is to rescue kuma. It may seem that RA is not a big deal to you,but for everyone in One Piece, they are a big deal. Most wanted man dragon and hes known by almost all pirates.