WWE looks and uses him as a good hand. He makes his opponents look like gold. But his work is showcased and he's put over, in other ways, without winning. This is a simple booking strategy that's been used for decades. It allows for the face to look more heroic while also allowing the last roadblock (Wyatt) to stay in place. It's basically a strategy to put over the face, but keeping the heel credible enough to be able to put others over and still have an effective drawing factor.
You look at guys like Vader, Mark Henry, Umaga, Andre the Giant and Kane. With the exception of Andre the Giant, they've all been monster heels with little to no major success in the WWE. Even Andre can't be exempt because his "first" loss came as soon as he turned heel, and put over numerous names afterwards, but was good enough to keep putting people over.
Vader, was a great star in WCW but this type of push fell into his career during his WWE run. He was the man that was used to put over Mark Henry and Kane, and was good until he was jobbing to guys like Marc Mero which was when his credibility was gone.
Umaga was never a world champion but was able to get CM Punk over before his big break. He made John Cena and Bobby Lashley look like a million bucks, despite doing the job within three months of each other. He also allowed Jeff Hardy to transcend into the main event.
Mark Henry has had an on/off again run as a monster heel, but the fact that he can still be pushed like that shows that it's working. His run as World champion was a great run, but he was able to make Daniel Bryan look like gold, and was a stepping stone and a vital part in allowing him to engage the main events of the WWE.
Kane is a prime example. He has put over everyone, but is still credible enough to come back to a good pop and put on a good match. We have super fans on this forum, and he's been active for 19 years. That's an amazing feat, and proves that titles don't prove longevity. He's convincing enough to put people over, without hurting his image. It's a great fit for Kane, at this point in his career.
So basically, they kind of aren't wasting his talents. He's being used good, since we have a vocal amount of people clamoring for his success, which is a clear sign of being over. But they kind of are, because Bray can work this type of heel, and a champion monster heel with solid singles success.