Savings may be good for the future but they can't be relied on to get the Fed out of a hole
There's a train of thought with increased savings that is, if things turn sour that money will pull the economy through.
Here's how Reuters view it from the data;
"...but a jump in savings suggested there is enough muscle to boost consumption in the months ahead"
That's often a pretty false suggestion as if things go south, the last thing people do is use those savings to splash out. What people tend to do is tighten their belts further in readiness for any hard times that they may need those savings for. That's the sort of outcome that leads to slowdowns not "boosts".
The Fed needs to know that because the US consumer isn't going to be the Fed's rainy day saviour if the economy does start weakening.
Increasing savings is a very good thing for Americans to do as it puts them in a better place to weather any trouble down the line. It doesn't do the economy any good as it relies on a chunk of that money to boost growth. It's the old 'rock and a hard place' scenario for the Fed in deciphering what the economy is doing. They'll be hoping that over time they will see more money shifting from being saved to being spent but there's a very thin line there.