When will CPUs be able to mine 'em? Does anyone think that's a possibility?
That feature is coming soon, it is possible but likely won't be too profitable.
Also could someone please explain the difference between CPU and GPU and why Crypto Miner isn't compatible with CPUs?
CPUs (Processors) are something every PC needs to operate. It's what runs your Operating System and any programs on your Computer. It also
handles displaying graphics if there is no GPU available, but is way slower than a GPU.
GPUs (Graphic Cards) are a peripheral device able to perform more difficult operations faster than CPUs. A lot faster. They are what makes games look fancy and run smooth.
Cryptocurrency Mining depends on fast calculation, your Computer needs to solve complex math problems when participating in a Mining Pool. For this under most currencies a GPU is almost enough, some cryptocurrencies like Bitcoin are at the stage at which you won't get far with a GPU though, you need
more powerful stuff there.