Based on the pictures, your mini probably isn't going to be competitive showing in the halter classes, but I would definitely pursue the obstacles and jumping. Any given bloodline, even the best known, are going to have good and poor representatives. One couldn't say Blue Boy bred horses are good or bad. There are some amazing Blue Boy bred horses and there are some pasture pet type blue boy bred horses.
The smartest horse I ever worked with was a by a horse named Blue Patent, who's a paternal sibling to your horse's sire. She was reasonable competitive in halter locally, but she her strength were the performance classes. She was a quick study and precise in her every move, and she was 100% reliable.