Because being useful is not nor has ever been a valid argument for keeping things. WP:USEFUL is the piece that better explains it i believe.
On 9/9/07, Bryan Derksen bryan.derksen@shaw.ca wrote:
Brock Weller wrote:
I never said they were useless, i argue that they dont meet our mission statement 'wikipedia is an encyclopedia', fail WP:NOT, 'indiscriminate collection of information' and are usually sourced to trivia works or put together by the editors, failing WP:NOTABLE and WP:OR. If you need help understanding my position, feel free to ask for clarification before setting up strawmen, it will help you effectively make your point next time :)
If they're not useless, they shouldn't be deleted. I don't see what's difficult to understand here.