So do I ...
I am sure the methodology could be applied to any trading asset. Go Long at bottom of channel and short at the top.
Yes, that methodology can indeed be applied to any trading asset, and in itself it will produce a similar result with any: an overall loss of money.
As you rightly say, it's way too simplistic, and - as you can easily verify simply from backtesting it - it doesn't confer an edge.
Keltner Channels are basically a variant of Bollinger Bands: the similarity between the two is that both show volatility-based deviations around a moving average of prices; the difference between the two is that with Bollinger Bands, the deviations are SD-based, while with Keltner channels they're ATR-based. That's about it.
Here's a simple explanation of why what you've described above
isn't profitable overall: the principle is one of "mean reversion", as many traders (perhaps unwisely) call it, and it lets them down on the positive-expectancy front because
the mean itself is a moving one. In other words, the price can be at the bottom of the channel (lower line of Keltner, or lower Bollinger band: the principle is exactly the same), and "revert"/"rise" to the midline ("mean-reversion principle") but actually
drop further in the process, because the moving average midline is itself also moving, while the price is. So, yes, it "works" in the sense that when the outer lines are touched/breached, eventually the price must revert to the midline ... and that's what many people find attractive about it, but the point they're typically missing is that that reality
doesn't actually predicate which way the price will have moved, overall, by the time it's actually done so!
(And that's without even mentioning stop-losses and risk management at all, which complicate it further.)
Like so many things, it sounds good until you try to make profits from its "positive expectancy", the inverted commas in this case signifiying that
it doesn't in itself have one. Not on NQ, and not on any other instrument, either.
The
specific mistake to avoid, with such things, is imagining that it "must" somehow be profitable, if only one "confirms" its "signals" by using it conjunction with another indicator as well. This line of "reasoning" is often an attractive and appealing one to aspiring traders who attribute to indicators predictive powers they don't really have - which tends to be something of a triumph of hope over experience.
Of course, that's
not to suggest that it has no possible use or benefit at all - but it's not capable of providing positive-expectancy trade
entries, in itself, in the simplistic way described above ... perhaps not least, overall, because "entries" themselves are by no means the most important component of trading with steady profitability, anyway ... but again, the aspiring traders who attribute predictive powers to combinations of indicators do, in my experience, tend to be broadly the same ones who also confuse "entry methods" with "trading systems"; they often harbor, also, the illusion that "if they can just get the entries right, everything else will somehow, magically, manage to work itself out successfully".
Hope these few thoughts help ...
, 
and viewpoint at any given moment in time along that fixed chart movement environment box,
[Edit note, the only disadvantage of posting something like this, seems to mess them up for while.LOL]I measure the main trend+ use that more than buy @ KC bottom or short @ KC top