Gann is a an enigma, much of it his own doing. Intentionally and/or otherwise. The only thing I use of his is the Square of 9 grid and Gann Fans - last chart image. And the only time I ever downloaded a free, aka bootleg, copy of a trading book (paid all others, 4 shelves full) was for The Definitive Guide to Forecasting Using W.D. Gann's Square of Nine by Patrick Mikula years ago before the Kindle version came out but I hate reading books off of a screen and the hardcover version go for $100's so what's a guy gonna do. Endless rabbithole is the very definition of trying to learn Gann's stuff. Most of it pseudo mumbo jumbo. For instance a novel by Gann called "Tunnel Thru the Air", supposedly the holy grail time/price vibration is hidden in its pages. A book I did buy but was disappointed in was The Trading Methodolgies of W.D. Gann by Hima Reddy. But anyone can post away, if they care to, about Gann in this topic.
Besides the 50% retracement there is prior support turned into resistance right on top of it (see far right values are overwritten each other) and zone for completion of wave B of ABC correction - 100% fib projection of lower level wave a from wave b lands right on 50% retracement 4119.75 wave c 1 tick higher. Too much clutter to chart to show it. Again fibs work well but not in isolation. Price, time pattern, momentum and trend, as mentioned, all need to be considered.
Grab a homebrew and round up the chirrens ...maybe they'll learn how to pay for their own damn college edumacation. It's story time again with Grampa Larry... Fibonacci: 1/9: Larry Pesavento Fibonacci: 2/9: Larry Pesavento, etc.
This is a post that I made in the thread "Prove to me that Technical Analysis Works" on Tues Morning July 19th (Post 317). This shows how Fibs can be used when the most important one, the 61.8% retracement is respected numerous times. The context was I was having a little spat with wmwmw as he made a call but refused to say what he was basing his call on. He called my analysis below garbage. Ya'all may thing so as well but I will always believe the Fibs have their place. I was not expecting this kind of answer especially your last sentence. So I will give the analysis that I expected you to give explaining the TA in this situation. See the chart below. You have a low on June 17 and a peak on June 28. After that you had 5 days that were spike down "pin bar" lows all in the area of the 61.8% Fib retracement of the June 17 low to June 28 high. Thus with the strong move up on Friday the 15th there is a TA expectation that this will support a move higher with a stop below the pin bar lows. That is your "holy grail" although you probably did not throw in the Fib analysis which most people on ET do not find a useful tool.