I have a Flight Sound X adapater that someone gave me and the thing is great. I have it on my computer and plug my lightspeeds into it. I use it to listen to things and also to record narrations on Camtasia videos.
Even a $10 headset for a computer sounds better than a $1000 aviation headset with the Flight Sounds adapter. So I would definitely recommend against getting one to avoid buying a separate headset for your computer. I agree it's a great way to test aviation headsets on the ground, and it's also great if you want the best realism for virtual ATC networks like PilotEdge, where most people are using cheap computer headsets and it spoils the realism because they sound way too good
If money is an issue, a passive DC H10-13.4 is a quality unit that will last a lifetime. I have several, and they are my passenger headsets. If you are going to be doing this a while, go for an active headset. Lots of good ones out there, but the Zulus are affordable and good quality. I've had a 1st gen Zulu Lightspeed for almost 10 years and it's still holding up.