Apart from the fact that the is a great indicator for general bullishness (or bearishness) in the market, it plays a vital role in the ending days of a bull-market.
In the screenshot above you can see the 50-week functioned as a strong support after the 2014 top had been reached. BTC saw an +80% increase in price after hitting the .
A similar thing occurred after the 2017 top. After BTC hit the 50-week we saw a strong move of around +50%.
Not saying that history will repeat itself again, but I think the 50-week offers a nice perspective nevertheless.
As you might see on the current chart of BTC , we've already hit the once before. Furthermore, we're currently trading at the itself. So, in case that the will hold, we might see a ~50% upwards move in the coming weeks, bringing BTC back to around $43k.
On the other hand, if this week's price will close below the 50-week we should be prepared for a further fall, potentially even hitting 25k in the near future.