You're correct in your assumption. Moving averages give a more general trend of the market. Having quick price jumps will muddy the results on an MA chart, and won't really reflect the day to day volatility of price as much (imo). However, you can be a day trader basing your strategy off of MA charts, you just have to know what to look for. It looks like the guy in your video encourages buying on MA crossovers, which is a valid strategy.

If you're getting into charting, you should open a free Tradingview account, and mess around with the things on that site. You could try that guy's strategy if you'd like, or there are hundreds of other indicators you can use. Either way, knowing how to read a chart will help you make more money in the long run.