The difference is that the tower was built and it exists and can be used for another project if not for the original one. If you ignore corruption for a second

The difference is that the tower was built and it exists and can be used for another project if not for the original one. If you ignore corruption for a second (not that you should), the problem remaining is the original project died without a replacement in the near term. This looks surprisingly like a waste of money, since the tower has no immediate utility. However, it has long term value and that is important. Doing busywork would have amounted to building the tower and destroying it to recoup the land value. If corruption was involved, it should be investigated separately. But the tower should not have been scrapped for this reason alone.