Because crowdsale prolongs listing the coin on the exchanges i think. As little as is bearable to wait 2 months for a signature, and then be part of the project as investor as well and find all sort of news. I remember quite a few campaigns that did hit their threshold on funds and goals and still extended the campaign and had hidden hard caps. I figured most of campaigns which gathered many investors (rather then few wealthy ones; aka whales) usually are more professional on communicating.