Line Charts explained
A line chart visualizes historical price action by drawing straight lines between consecutive closing prices. It is one of the first tools that any trader should master because it helps quickly view patterns in price over time, such as monitoring trends or spotting support and resistance levels.
Regarding trend-spotting, line charts are useful for long-term investors because they can track trends in assets easily without having too much extra information cluttering up the picture unless it's needed, such as indicators like moving averages or oscillators.
So if you’re trying to create a historical picture of prices over time and how they changed, this might make sense - but if you’re looking to trade during these fluctuations (and profit from them), then you would likely want to avoid a line chart because it does not provide enough data to make a well-informed trade.
On the other hand, let’s say you’re an individual who wants to get involved with day trading but has little experience with it. You do not know what kind of assets are out there or how to get involved. Line charts are good for beginner traders because they are fairly easy to understand. It could give you information on the markets, showing trends and volatility over time - this could help you paint a picture of the market by giving you historical reference points (it would not necessarily be useful for buying or selling at any given point).
As far as the other charting styles are concerned, the difference between OHLC (open-high-low-close) graphs and line graphs is the fact that in an OHLC graph, each transaction during this period of time has its own data point while in line graphs, only the closing price of the period is plotted.
To sum up, line charts are a good starter, but other styles may be more useful when implementing trading strategies.