Moving averages are mostly only used by amateurs these days. As has been mentioned they take the average closing price of an asset over a set period of sessions and that's the value.
The problem with this is that close prices for various sessions aren't always useful. VWAP or Volume weighted average price is a much more useful tool because value in a market is dictated by volume. Rejection of heaviest volume is a more powerful signal than rejection of the average closing price of whatever session you're looking at.
I disagree. I think you're missing what MAs are all about: time. It's not just about price/volume history, but time, since mean reversion is such a crucial aspect of market analysis. That's why very popular tools like Bollinger Bands still use simple MAs (and standard deviations thereof).
I like to use traditional MAs for golden crosses and death crosses (signs of strong trend continuation). 200/50 MA crosses are good performers. When it comes to volume, I prefer to focus on high relative volume bars (capitulation points) and volume profiles to find support and resistance levels. OBV is useful as well.