For a whole bunch of reasons, ie to pick a few:

- you may have a NWC situation where cash isn't paid up front - you may want to continue to invest in R&D / tech development on newer projects that aren't currently generating revenue - you may simply want to grow faster / hire more than your current financials can support

It seems pretty logical to me - at that point, you probably have a solid stepping stone, and want to decide what to do next.