Just for gym fighting

Nope, for defense it is not bad.

Its is Offensive due to HB.

HB is too easy to dodge when battling the AI.

Depends on your standards. DT/HB is better on attack DPS than DB/DC, but only just. It's about tied with SW/OR, and behind the other two DT movesets. It's also worth mentioning that DT is slow so you won't be able to spam and still dodge.

However, it's the second best defensive moveset, behind DT/OR (by a pretty large margin) but ahead of everything else.