This is my take. Due to the lack of response to your question, you'd think no. However, serious professionals do use cot data. But, it has to be taken for what it is, just another indicator. Still needs confirmation. I do use it. Let me rephrase, I'm learning how to use it. Simply, right now I look for the extremes in commercial positions, which would therefore mean the large specs are the other way. Then I just keep it in mind until I see some price action evidence that the turn might be at hand. Once I see the large specs start to unwind positions, then I feel I'm more on track taking the direction of the commercials. It is important to look at the the commercials relative extremes against open interest.
The way I see it is that due to the lack of replies to this thread, there is something valuable in the cot data when used correctly. You don't ultimately get serious traders writing on this site as they have better things to do and wouldn't necessarily want to disclose what and how they do it.
I have posed questions regarding point and figure charting a couple of times with no great response. The lack of response indicated to me that learning it was therefore worth doing and I'm now glad I did.
Use ET as a contrary indicator. If the masses don't know what you're talking about, then it's likely to be a valuable.