You can build any logic gate you want, with layout being the hard part (just like IRL...). You can build a computer in Minecraft if you want to. I believe that several people have [1].
To be honest, I think it's a great way to learn about electronics. I know what all the gates do from having taken EE classes, but Minecraft has made some of them a bit more intuitive. Maybe it's just because you can see the things being energized/de-energized, but it does help me think about the different gates/latches/etc. and their interactions.
[1] This is but a small sample of things that might be called computers that have been built in Minecraft: