Does it really work or not?
It can work and it can not.
Some people blindly believe in certain TA, and other people completely discredit it. I think that it probably falls somewhere in between. Some historical trends can still be referred to in order to predict future outcomes.
TA is still speculation, and just because that someone says it will happen, doesn't mean that it will actually happen. TA does work better in the short term I believe, if you are watching BTC for the long term you're probably better off going with your gut feel.