Keep your mind open: if that's what you believe, it doesn't mean it is so. A channel has a width, a slope, a structure, and the price it includes is obviously measurable.
You need HH, HL, LH, LL to draw trend lines. If you think those occur in the short term, the joke's on you.
It seems that you think your view of the trendlines merits is correct. Let me tell you that I know for a fact, that you're mistaken.
OK, tell me how you get measurements of trend strength and/or trend quality out of them and I'll be convinced.
Until you explain how any of that translates into a measurement of trend, you've demonstrated nothing.
OK what's the minimum number of points you need to draw a reasonable trendline? I only need 4 bars for the KER. Is a 4-bar trendline something that makes sense? I don't know, and don't care enough to any testing myself. I assume those who do care about trendlines have done or are willing to do this testing themselves.
Mathematically you can do it with 3 points. Either HH, HL & HH or LL, LH, LL can define bull or bear trends. The arc of the first two points can be applied to the 3rd point to predict the arc of the 4th. This is trend direction. Trend strength comes from the level of price pull back or rise associated with the HL or LH of the trend. I've always called this the rubber band effect. When the energy is released the target HH or LL distance measures strength. Took me years to prove this but it works flawlessly.