Does it matter if it's cooked or not? I guess I wouldn't eat the uncooked kind, but for the English translation I don't see that it's wrong if I don't mention it's not cooked.
Mchele is dry rice grains. Cooked rice is wali. So there is a reason for the distinction, and it does need to be taught. How does the system know you understand the difference between mchele and wali if you just type "rice" for each? You might just think they are synonymous.
Yes, typing cooked or uncooked is a pain, and there is probably a better way they could have handled it. But hey, the annoyance at the memory of having to do so might help the words stick. ;)