I am doing basic research. I do trade my own account, global macro analysis with a simple trend following overlay. Fundamental factors drive the prices, and technical analysis can aid in making short term trading decisions (at least that is the hypothesis I am testing.) I am very much a developing trader, and I think the best way to progress is to trade and learn continually. My goal is to eventually have the skillset to profitably trade my account in this manner and make an excellent living.
To your point "why would I want to know," if I knew with a high degree of certainty that in the short run the markets are just a standard normal, and that Technical Analysis is useless, I would just make short term trading decisions based on that concept, throw all forms of TA out the window, and focus my time on global macro fundamental analysis. I'm trying to sort out what is useful and what is people seeing "bunnies in clouds."
Your basic research will likely lead to a trading framework (a business plan), which I believe is necessary for consistent profitability. I had plenty of good ideas as a beginner but without a well-researched plan, I failed each time. Once I compiled the MAE/MFE stats surrounding certain patterns under various price environments leading to the patterns (pattern + context=setup), I had a framework for trading.
Technical analysis gives you full view of context (price behavior in the minutes, hours, days, weeks, months, and/or years to the left of right now) and patterns (a price action footprint such as engulfing price bar or a 1-2-3 or a narrow range consolidation flag, etc.) that lead to significant (by your definition) price moves more often than not over each series of N appearances of the setup.
There are many setups that produce positive expectancy for a favorable price move of at least X ticks before an adverse price move of Y ticks.
What confuses aspiring traders and causes them to deduce that markets are random, all edges are transitory, TA is worthless, etc. is the experience of having tried a lot of TA and indicator-based ideas and failed.
Trading based on individual price bars, candle patterns, and indicator readings result in failure because the extensive research necessary to determine the context under which these "trade bites" convince enough traders to join one side and overpower the other side was never completed.
The other issue is that specific price bar patterns (footprints) that indicate the likelihood of "herd follow-through" in a given direction under certain conditions don't look exactly the same every time. Those looking for certainty or perfection will likely find themselves unable to trade their own plans for this reason. Their risk-averse brains will offer up one reason after another why the setup doesn't meet exact plan criteria (despite the fact that close is close enough).