Has there been any significant correlation between its predictions (Short/Mid term UP/DOWN) to actual price movements?
If you are talking about Technical Analysis in general, we would need to write a book to answer that.
As for Technical Analysis applied to Bitcoin, just look at the date when the predictions were made, look at the graphs and compare. During the last couple of months:
He wrongly predicted a short term rally starting at $14 at the end of July
He correctly predicted the short term fall to $6 at the beginning of August
He has been predicting a long term up trend for two months that hasn't happened yet
Overall, I think his analysis are well documented and based on market indicators that work very well in other markets. However, I am not sure if the Bitcoin market got to the point where Technical Analysis plays an important role for price movements. No one can really tell because this is not an exact science.
Personally I think technical analysis is not useful for Cryptos, especially in the long run. I traded commodities and forex for a while and moved to Crypto's more than a year ago. Crypto's are better analyzed along the lines of "Start up" companies or "New technology" rather than commodity/forex trading. They are heavily influenced by news and politics and all altcoins are influenced by the grand daddy Bitcoin. Trendlines are handy and I created one over the whole of bitcoins history and it has been pretty accurate for predicting the future so far. I uploaded a video on it if you're interested the link is in my profile. Starts off a little slow but pretty valuable if you trade bitcoin.