These are mostly for government structures, military etc. No one is using them (or, say, Elbrus) at home for PC's/workstations. Maybe only some geeks and just for fun. Usually you can't even buy them in normal computer stores (at least I have never seen any).

Maybe someone had used a grid of those, but alone that CPU is quite weak for supercomputers ;)

This CPU is used in a printer: http://katyusha-print.ru/ (but I doubt the product is any widespread - there are no such devices in stores, anywhere)

For PCs it's x86 (with a small fraction of ARM) - just like (almost) everywhere else.

It's probably only used in military technology and government devices; the only advantage is the control of supply chain, security (less risk of backdoors with manufacturer cooperation) and thus suitability for local defense industry. For example, I recall seeing some announcement about a locally designed tablet computer with this or similar CPU, designed for military map/geolocation use.

Both for supercomputers and ordinary workstations they'd use the same hardware as everyone else, the price/performance is better that way due to economies of scale.

No, actually these are mainly for IoT kind of use, multimedia and network devices, CNC systems (actually some companies already have ready CNC solutions with Baikal).

As for the PC (like in office PC) - https://en.wikipedia.org/wiki/Elbrus-8S is the main trend for state departmets and other places were security should be higher than your usual office. 8S will be replaced with 16S in 2018.

See http://www.cnx-software.com/2016/03/03/tavolga-terminal-tp-t...

I think homegrown chips like these have many application in weapons systems. Russia wouldn't want their UAVs or missle defence systems to run with Intel CPUs or other COTS CPUs with embedded blackbox OSes for example.