It would add a defense line along the Dneister, which defines the Eastern border of Moldavia. Its a pretty good obstacle.
And there are a couple of other good river lines inside Moldavia which would also work, like the Prut.
Moldavia would, at least, add defensive geography to the southern flank of NATO.
We cared a lot about it a few years ago, when W was president. Russia has cared a lot about it too. It has to be important strategically for those two things to be true.