Suppose you find a question titled "How tall is Jackie Chan?" in Stack Overflow or any other SE site. It is off-topic. So you flag it:
This question doesn't fall under any of these. So you have to click "Other" and explain that it is... well... off-topic.
Wouldn't it be more appropiate to have an additional option saying "This question is not about programming (or whatever the SE site is about)" rather than relying on the "Other" option?
I considered that the question might be flagged under other reasons, like "It is very low quality", but according to the description this option is used when there are formatting problems or it is hard to read / understand.
Also considered "It is spam", but the description says that it is for when the question is advertising something, but in this case the asker legitimately wants to know Jackie Chan's height.