Deca benefits come from it progestageinc effects. THG (tetra-hydro-gestrinone) is progestagenic too.
Dealing with TOO low progesterone is hard(joint pain, depressed immune system, etc).
Deca is too long lived, when problems (deca-dick, gyno, fat gain, etc) develop, youll have them for a couple weeks after discontinuing.
With a short acting progestagen, when problems begin to show up, theyllcome to an end a couple days after discontinuing.