The chart pattern and reading is what give cryptocurrency trading that professional look compared to gambling, although cryptocurrency market speculation is also like gambling because as a market speculator, you don't know what exactly will happen in the market in the next second, so for that, is left for you to at least make an analysis of what the market could and should look like and make your predictions along that line of thoughts, so somehow both gambling and trading have some similarities and features because luck have a tiny place in trading and while luck have a higher play in gambling.
You are right, we as traders do not know what the next move of a particular chart will be, so I apply something very simple, it is to see what has happened previously to give me an idea of what could happen, otherwise I would not make any kind of prediction because that is a prediction and it is not something I am an expert in, so I base myself on the routine or pattern that I can give, so for market speculation, many use their tools, indicators and everything they have at hand, all of that is valid.