If I had a solid understanding, I wouldn't be here on an internet forum asking condescending ******* strangers stupid ******' questions.

However, I suspect my understanding isn't quite so fundamentally lacking. You have a shifter that's got some preset tension levels built into it and a cable that runs from it to your front derailleur. The derailleur itself has spring tension built into it, so the cable tension only pulls it in one direction. When tension is loosened, the deraileur goes the other direction under spring tension. The two adjustment screws limit the amount of play to the inside and outside.... left for inside, right for outside. This keeps the derailleur from throwing your chain off the rings and fine-tune position. Based on what you've just said, I'm going to assume the inline tensioner does exactly what I surmised it does- just allows you to adjust tension without having to get out a hex and retighten your cable at the derailleur.

My lack of understanding is why the inline adjuster is even necessary t begin with? Seems like it's CAUSING more cable slop than it's fixing. Have to adjust it damn near every day.... hence my statement that it seems to have some kind of malfucntion.

But otherwise, there just doesn't seem to be all that much to this stuff that an afternoon of youtube videos and a couple of attempts can't teach you.