Defensively, the ridiculously low response time of teleporting ships like that makes them pretty awesome for cleaning stuff up in an emergency, like you've noticed with the raiders. Anything that makes it through your defenses or comes from somewhere you weren't expecting it can be dealt with or at least held off for long enough to bring in enough stuff to handle the problem.
Offensively, they will tend to die horribly on their own if you just send them in. You can do some kind of fun/silly things with them, though, as long as they're not the main attack force. Something they're good at is being a diversion. If you can get the AI ships focused on them and chasing them around, you can teleport them waaaaay out to the edge of the system to draw them away, then send your real attack force in, or at least a bunch of bombers or something, and clean out the guard posts (or whatever your targets in the system are) relatively unmolested.
If you play around with them, you can come up with some support role kinds of things like that for them to do. You just have to get a feel for what kinds of situations they're useful in and not, which takes some experimenting and trial and error and error and error. Heh.
