My take, he never came there to kill Vanth, he came to intimidate the fuck out of the entire town on behalf of the Syndicate. They knew what they were up against, Vanth took out three Pykes without breaking a sweat and they took that seriously. That's why they sent a monster who could wing him on purpose and unload the clip on his bitch ass deputy without breaking a sweat. Its actually one of my favorite parts of this episode, that they set up how good Vanth was with a gun so you would know exactly how outmatched he was by Bane when he showed up.
Also, its just great storytelling.
Gotta admit, this series has been very up and down even for a shill like me. But the last two episodes have been so fucking good they have got me fucking hyped for this finale and next season of Mando. I'm primed for nerdgasm or epic disappointment. Bring it.