I think redundancy could be used to create greater precision and detail.
For my personal application, extra resolution at the top is actually a good thing, because that is where the trusses of a roof are located. I don't need extreme precision, but I at least need to see them,and the scan needs enough resolution to do that. I would even accept a much slower scan if necessary to get a useful resolution.
The floor resolution is much less important to me. So, ideally, you might aim the scan a bit higher. Others may need the lower area. So, ideally, you would have some ability to choose between the various options.
I think there are many who really want a full scan of a room. For many, the missing scan areas on the top and bottom can just be assumed to be a continuation of what is around it. But, for full coverage without assumptions, I imagine that really requires multiple scan locations, to cover everything. So, the multiple scans may also cover the gaps of coverage at the top and bottom. Then, it becomes necessary to register the scans.