Without a clear TK, the result is XS
No matter how bottomless your pockets are, and how boundless patience you would not have, you still want to see your project ready not in a year or two, but in the near future. And not for a cosmic, but quite sane price tag.
Competently prepared terms of reference, clear and clear, will help to significantly reduce the cost of project development. This applies to both time and finances. Having a clear idea of how and where to come, it is much easier to achieve the goal. If you only have a general idea of where you want to come, there is a risk of getting lost on the way at all.