There is a lot of variance in how much time it takes for a startup to raise - some are already done before Demo Day, and some take a couple of months or they postpone it for later.
Although it looks like a waste of time from the distance, since it prevents you from building the product, in our case it was actually a very useful and formative experience, I'd dare to say even the most of all parts of YC. Being an OSS, developer and tech oriented startup with no revenue it made us very aware of that and forced us to learn about how we can get there. As the result, we solidified our vision and actually feel much more confident about it now than before the fundraising.
Although it looks like a waste of time from the distance, since it prevents you from building the product, in our case it was actually a very useful and formative experience, I'd dare to say even the most of all parts of YC. Being an OSS, developer and tech oriented startup with no revenue it made us very aware of that and forced us to learn about how we can get there. As the result, we solidified our vision and actually feel much more confident about it now than before the fundraising.