I've worked on a ton of businesses cases that require it. This is what I worked on for years.

It's generally a large company, large issue sort of problem. You can throw millions in hardware/software into a problem that saves you 100's of millions.

We can solve it quite efficiently. You can define an index on a columnstore table and we will maintain order on a per node basis

Analytics, BI, ...

More about rows/second it's about lowering minutes/operation.

Some people do... but this is about showing the potential.