Will this computer be used close to 100% /was the old super-computer just not enough?
* Weather modeling
* Nuclear Research
* Car crash simulations
* Electronic Design Automation (ex: mathematically proving chips are correct)
* Protein folding: looking for new chemicals for medicine.
Etc. etc.
There's a huge need to grow our supercomputer capacity. I bet you that every major field has a use for a super-computer.
I think there's an element of bragging rights. But the USA buys "practical" supercomputers most of the time. There are designs that push out more FLOPs but are less useful to scientists.
The hugely powerful interconnect and CAPI / NVLink connections on this supercomputer demonstrate how "practical" the device is. Most people are RAM constrained, or message-constrained, and these are the biggest and best interconnects available in 2018.
Interconnects are NOT a "bragging" metric, very few people look at it. Most people look at the Linpack benchmark (purely FLOPs measurement). However, experts can tell when a supercomputer is built with a poor interconnect and purely for "bragging rights" reasons.