Nice analysis, bitcoin did not fall below $ 3100 and ethereum did not fall below $ 100. but although there are support and resistance points, leveraged trading and futures exchanges they can manipulate the price as they wish. and in such cases, technical analysis it does not work.
TA might not always work because of market manipulation, but it can be applicable let's say you wanted to see a pattern in the past that may help up decide for the future.
Although you have to take into consideration that the market is still young, so the data might not serve its purposes. So for me TA could work if there's a lot of sample data already. But right now if you're doing TA for short term purpose, I guess it won't be applicable because of the volatility of the market. Conditions changes very quick that's why its really hard to do short day trading here.