A few months ago, the DXY dropped significantly, I remember it fell around 1% and reached 97.61.

It's not a small move when we talk about the dollar index, because that means the dollar weakened against other currencies.
Many traders were watching that movement because the DXY is one of those indicators that tells you how the dollar is doing in global markets.
When the dollar index falls like that, you usually see effects in other markets, currencies move, economists start analyzing what's happening.
Honestly, following the DXY gives you a good idea of currency market trends, so it's not something you should ignore if you trade or invest in these markets.