I study their builds, play their builds, tweak their builds, completely bastardize their builds into barley recognizable facsimiles, borrow pieces like paragon setups or synergy ideas for my own builds and make my own from scratch.
I really don’t see the big deal or any need to take a position that they are good or bad or anyone should or shouldn’t use them. at the end of the day, I run a mix of what is most powerful and what I find fun for different parts of the game without regard to the source.
I will also admit in spite of putting in a fair bit of effort I have not come up with anything original that can easily handle top tier like high pit or T8 
Best accomplishment so far on full homebrew is a S5 FO/Hydra than can handily clear T7 and pit 101 running all unique and mythic that requires 0 tempering.