I use it quite frequently for aerial approaching. Like Yojimbo mentioned, you can follow up with jabs or sometimes I would start from a very low % short hop> fair>utilt>utilt> fair. However, the timing is crucial and generally on very low %'s, sometimes not more than 15% I have only tried this on medium to heavy characters and highly doubt it works on smaller, lighter characters.
And much like Pika Kong mentioned, I have found it hard to get a solid KO on an opponent other than trying to punish with fsmash or usmash (which I REALLY enjoy the good range of). Other forms of punishing I suppose I would try is side b or down b (of course, requires mad amounts of good timing and/or prediction). The only main thing I really to work on haha
Not sure if mentioned before, but fully charged shuriken, as far as me, has been majority of the time successfully followed up by a fair once the shuriken launches. Its useful for edgeguarding if landed and as I said, can be followed by dashing then fair'ing. This generally works for me on 50%+ but not too high as the launch from shuriken will be too great to follow up.