Ok, let's get one thing straight. Tom DeMark, whilst clearly a clued up guy cannot write clear English to save his life. That book, Market Timing Techniques is a complete nightmare to read. The third book, DeMark on Day Trading Options is the one to read before looking at the Timing Techniques book. I think the options one was written by his son. This third book was written to sell more books and they decided to call it an options book to make it different to his previous two. But, a much easier more logical read.
Yes, correct, due to the time it takes to get a completed Sequential count, it does enable you, well, more require you, to look at several different markets. It's easy to scan and see in a second if there are any completed counts, but if you're watching all markets all the time, then you see them brewing and you know that if you're looking at a daily, and yesterday was a 3 count, you can forget that chart for some time.
I employ other trading techniques as well, but Sequential is a HUGE part of my overall trading strategy. I'll take my outlook back to the monthly charts which when form a completed count I sit up and take notice. Weekly, then daily. If I get a weekly TD sell signal, then a daily TD sell, then I'm know I've got to get involved. I go down to 240's after that. Like anything, you get alot of false signals, but this is why you have to adjust your RR. When they call a turn, it can be very quick and wholesome let's say.
People use this on much lower time frames as well, down to 1 min charts. I find that it makes some incredible calls on the 15 min charts, but it's all about your timescale preference.
Would I suggest anyone rush out and learn this stuff? Not sure. For me it's the basis of my trading, but I've used it for a long time and know how to use it. Are your signals just as good if not better? Probably. If it aint broke, don't fix it. Usual stuff, what works for one, doesn't for others.
For me, every single chart has Sequential on it.