I guess it all depends on the teacher, because I changed my subject selections from Modern History to IPT (because I liked the teacher--I had her in year 9 & 10 for computing studies) and I'm so so so so glad... Even if it doesn't count towards my UAI, it will still useful to me because I recognise that the world revolves around technology and if you know the least bit more about it than the next person, you're that much better off.
I know that people think that it's a boring subject and that heaps of people drop it at the end of year 11, but if you have that attitude, it will just make it seem even more boring to you. I'm lucky to have a close-knit class--we actually have a lot of fun...and we hardly ever do stuff on the computers. I'll admit that the content can be boring, but the lower amount of stress really helps.
However, I really hope to do really well in IPT or else 4U maths will have to count
and I don't feel so good about that...
So, if you're in Year 10 considering doing IPT and you do practically nothing in computing studies (and you like it that way)...don't do IPT.