Should "What are the advantages of X" questions be closed?

I see that some are open, some are closed, so I wonder what the policy is.

Examples:

- http://superuser.com/q/730315/116475
- http://superuser.com/q/924734/116475


[More examples](http://superuser.com/search?page=1&tab=relevance&q=%20what%20are%20the%20advantages%20of%20).